Genetic studies of corn (Zea mays L.) anther culture response

Summary Anthers of two maize (Zea mays L.) inbred lines, DBTS (P₁) and B73 (P₂), their F₁, F₂ and first backcross generations — F₁ x DBTS (B₁), and F₁ x B73 (B₂) — were float cultured in YP medium to study the inheritance of corn anther culturability using generation mean analysis. Significant effects of generation were observed for the three traits measured: anther response (%), frequency of embryos (%) and anther productivity. Variation among the generations was similar for anther response and frequency of embryos: no significant differences were found among the P₁, F₁, F₂ and B₁ means, but the means of P₂ and B₂ were significantly lower than those of the other generations. For anther productivity, the F₂ generation tended to have a slightly higher tendency for multiple embryo formation. A simple additive-dominance model was adequate in explaining the inheritance of anther response and frequency of embryos, but digenic epistasis (additive x dominance) was involved in the inheritance of anther productivity. Additive genetic variance was higher than non-additive genetic variance for all the traits; however, only environmental variance was significant. Narrow-sense heritability estimates were 65% and 75% for anther response and frequency of embryos, respectively. Significant inter-plant variation was observed within generations, even for the inbred line DBTS, but isozymic analysis involving five enzyme loci did not reveal any genotypic variability within the inbred lines DBTS and B73.     

Analysis of quantitative trait loci which contribute to anther culturability in rice (Oryza sativa L.)

Anther culturability of rice is significantly different between indica and japonica varieties. A doubled haploid (DH) population was established via anther culture of an indica/japonica hybrid on SK₃ medium, which had been shown particularly suitable for anther culture of indica/japonica hybrids. For analyzing the quantitative trait loci (QTLs) responsible for anther culturability, anthers of the DH lines were again cultured with SK₃ medium and parameters for four traits representing the anther culturability were surveyed and analyzed with the molecular map constructed from the same DH population. The parameters for four major traits were as follows: callus induction frequency (CI), green plantlet differentiation frequency (GPD), albino plantlet differentiation frequency (APD), and green plantlet yield frequency (GPY). All four traits displayed continuous distributions among the DH lines. The correlation coefficients between these traits were also tested and showed that there was no relationship between callus induction and green plantlet differentiation frequencies, but both showed strong positive correlation with the frequency of green plantlet yield. For callus induction frequency, five QTLs were identified on chromosomes 6, 7, 8, 10 and 12. Two QTLs for green plantlet differentiation frequency were located on chromosomes 1 and 9. There was a major QTL for albino plantlet differentiation frequency on chromosome 9. No independent QTL was found for green plantlet yield frequency. The results may be useful in the selection of parents with high response to anther culture for rice haploid breeding and in the establishment of permanent DH populations for molecular mapping.     

Elevated carbon supply altered hypericin and hyperforin contents of St. John's wort (Hypericum perforatum L. cv `New Stem') grown in bioreactors

For the high frequency selection of salt-tolerant doubled haploids (DHs) using rice anther culture, the efficiency of anther culture was investigated with different genotype, media condition and NaCl concentrations. The six F₁ hybrids obtained by backcross or three-way cross between indica and japonica differed in salt tolerance. The efficiencies of callus induction and plant regeneration was decreased by NaCl concentration and salt tolerance of donor variety, and those in japonicas were higher than those in indicas. The percentages of callus induction in Gyehwa 5 (japonica, tolerant) and IR61633-B-2-2-1 (japonica, sensitive) were 21.1 and 13.5% on agar medium containing 0.3% NaCl, respectively. The plant regeneration of callus derived from anther floating culture in liquid media was less than that on solid medium. In four F₁ hybrids, the frequencies of high salt-tolerant DHs were 21.4 and 8.9% in 0.3% NaCl medium and the control, respectively. The high frequency of salt-tolerant DHs could be selected in the callus induction medium (0.3% NaCl) and in the combinations crossed with salt-tolerant japonica as the third parent.     

Putative homozygous mutations in regenerated plants of rice

Summary Both normal and putative homozygous mutant (dwarf mutant) rice plants were regenerated from diploid seed callus, cultured in the presence of 1% NaCl. This trait was transmitted at least through the eighth genration (D₈) of regenerated plants (D₁) by self-pollination, as a homozygous mutation. However, the trait disappeared in the F₁, F₂, F₃ and F₄ obtained by reciprocal crosses of mutant plants with either control plants or with progeny of normal regenerated plants. Chimeric reversion of the homozygous mutant trait was observed and the revertant phenotype was transmitted stably to at least three successive generations. Similar dwarf types of homzygous mutation were observed independently in the two varieties, Norin 8 and Nipponbare, in an experimental series of ca. 3000 D₁ plants. The frequency of mutations among regenerated plants was calculated to be 1.8×10^-2. The mechanism responsible for these phenomena may be heritable gene inactivation induced by in vitro culture.     

Variation in Anther Culture Response and Fertility of Backcrossed Hybrids between Indica and Japonica Rice (Oryza sativa)

This study was conducted to investigate the variations of fertility, callus induction and plant regeneration in backcrossed hybrids between a responsive japonica variety (Mankeumbyeo, recurrent parent) and a recalcitrant indica variety (Ranta Emas, donor parent) to anther culture. The mean spikelet fertility of inter-subspecific F₁ and BC₁F₁ hybrids was 33.5% and 67.2%, and the spikelet fertility of BC₁F₁ among backcrossed hybrids showed the most extensive variation (a low of 4.5% to a high of 90.6%). The mean fertility and distribution range in BC₅F₁ hybrids were almost the same as that of the japonica recurrent parent (94.6%). The mean callus induction of F₁ and BC₁F₁ hybrids was higher than that of donor parent, and the distribution range in BC₁F₁ hybrids varied from a low 0% to a high 18.7%. The mean callus induction and plant regeneration of BC₄F₁ hybrids was almost that of japonica recurrent parent, and there were no statistical differences between BC₄F₁ and BC₅F₁ hybrids. These results may help to accelerate the introgression of desirable traits from indica into japonica rice using anther culture of backcross hybrids as a breeding strategy.     

The falcifolia syndrome of Oenothera: III. The general pattern of its non-Mendelian inheritance

Summary The falcifolia (fal) syndrome is a malformation characterized by shoot sectors with sickle-shaped leaves, which appears in hybrids between Oenothera suaveolens and O. lamarckiana and shows a non-chromosomal inheritance of a previously undescribed type. The determinants, their location in the cell, and the mechanism of their expression are unknown. The defect is the result of a cross in which mixing of two different cytoplasms occurs, without the usual predominantly maternal inheritance. F₁ progeny of reciprocal crosses show a quantitative difference in the frequency and degree of expression of the fal character. When the F₁ progeny are backcrossed to the parents, the percentage of fal is high in crosses to O. suaveolens and low in those to O. lamarckiana. This manner of transmission is observed regardless of whether the hybrid is used as seed or pollen parent or shows a normal or fal phenotype. F₂ generations from F₁ plants having either a normal or a fal phenotype always include a certain percentage of fal plants, although the latter generally produce a higher percentage of fal progeny. If a second backcross is carried out, plants that produce normal progeny on self-pollination behave differently from those that produce some fal off-spring when selfed. The latter are similar to the F₁ with regard to the transmission of the fal trait. Plants of the F₁B₁ yielding normal progeny upon selfing produce normal progeny in the F₁B₂ if the parent to which they are backcrossed is the same as in the first backcross; if the parents of the first and second backcross differ, a high percentage of fal offspring is obtained. Again, whether the hybrid is used as seed or pollen parent is not relevant. Exceptions to this behaviour have been observed only rarely in that the character of the penultimate cross is retained. There is some evidence of somatic segregation of the fal determinants, since sister plants may react differently; this suggestion is supported by comparing the progenies of different branches of a self-pollinated fal plant of the F₁ generation.Abbreviations F₁, F₂, F₃, F₄ First through fourth filial generation, obtained by self-pollination - F₁B₁ First backcross generation, i.e. the F₁ was backcrossed to one of the original parents - F₁B₂ Second backcross generation, i.e. the F₁B₁ was backcrossed to one of the original parents - F₁B₃ Third backcross generation, i.e. the F₁B₂ was backcrossed to one of the original parents - (F₁B₁)D₁ Descendants obtained by self-pollination of a F₁B₁ plant; further generations obtained by self-pollination are designated as D₂, D₃, D₄ - (F₁B₁)D₁B₁ Descendant or generation obtained by a backcross of the D₁ of an F₁B₁. Backcrosses of the D₂ and D₃ are designated mutatis mutandis - (F₁B₁)D₁B₂ Generation obtained by a backcross of the (F₁B₁)D₁B₁     

Linked epistasis for six quantitative traits in Indian mustard (Brassica juncea (L.) Czern & Coss)

Summary Gene effects, and interactions, and associations between days-to-flower initiation and maturity, number of secondary branches and siliquae per plant, and 1,000-seed weight and yield per plant were studied in a cross of Indian mustard (Brassica juncea (L.) Czern & Coss) using the parents and F₁, F₂, F₃, B₁, B₂, B₁₁, B₁₂, B₂₁, B₂₂, B_1S, B_2S, B₁F₁, B₂F₁, B_1bip, B_2bip, F₂P₁, F₂F₁, and F_2bip generations. A linked digenic model was adequate for all characters studied. According to this model, the main effects, additive and interactions between linked pairs of genes, were present in varying proportions for days-to-flower initiation and maturity and number of siliquae per plant. The contribution of linked epistatic effects, however, was much greater than that of additive effects. Dominance effects contributed significantly to the inheritance of days-to-flower initiation. Duplicate epistasis was observed for all traits except 1,000-seed weight where epistasis was of the complementary type. A complete association among the genes of similar effect (increasing or decreasing) was observed for number of secondary branches and siliquae, and yield per plant. Coupling phase linkage was observed for days-to-flower initiation whereas repulsion phase linkage was observed for daysto-maturity and 1,000-seed weight.     

Synergistic promotion of gibberellin and cytokinin on direct regeneration of floral buds from in vitro cultures of sepal segments in sinningia speciosa hiern

Summary This study reports the direct regeneration of flower buds from cultured sepal segments of Sinningia speciosa Hiern. Two types of floral bud regeneration were observed: regeneration of floral buds only (designed as B^F) and regeneration of both floral and vegetative buds (designed as B^F+V). The capacity of B^F regeneration was closely related to the location of sepal segments and the concentration of exogenous gibberellin (GA₃) and cytokinin in the medium. On the medium containing 1.0mgl^−1 GA₃, the addition of 6-benzyladenine (BA) significantly increased the frequency of total flower bud (B^F+B^F+V) formation, with the frequency up to 91.5% in the presence of 0.4mgl^−1 BA. On the medium containing 0.1mgl^−1 BA, the addition of GA₃ also increased the frequency of total flower bud regeneration, with the frequency up to 74.3% in the presence of 1.0mgl^−1 GA₃, but no further increase in regeneration was observed when the GA₃ concentration was higher than 1.0mgl^−1. The capacity of B^F regeneration from different locations of sepal segments was differential. The adaxial part of sepal segments gave rise to the highest frequency of 56.7 and 84.3% for B^F and B^F+B^F+V, respectively.     

Gene interactions and genetics of blast resistance and yield attributes in rice (Oryza sativa L.)

Blast disease caused by the pathogen Pyricularia oryzae is a serious threat to rice production. Six generations viz., P₁, P₂, F₁, F₂, B₁ and B₂ of a cross between blast susceptible high-yielding rice cultivar ADT 43 and resistant near isogenic line (NIL) CT13432-3R, carrying four blast resistance genes Pi1, Pi2, Pi33 and Pi54 in combination were used to study the nature and magnitude of gene action for disease resistance and yield attributes. The epistatic interaction model was found adequate to explain the gene action in most of the traits. The interaction was complementary for number of productive tillers, economic yield, lesion number, infected leaf area and potential disease incidence but duplicate epistasis was observed for the remaining traits. Among the genotypes tested under epiphytotic conditions, gene pyramided lines were highly resistant to blast compared to individuals with single genes indicating that the nonallelic genes have a complementary effect when present together. The information on genetics of various contributing traits of resistance will further aid plant breeders in choosing appropriate breeding strategy for blast resistance and yield enhancement in rice.     

Power of the joint segregation analysis method for testing mixed major-gene and polygene inheritance models of quantitative traits

Understanding the genetic architecture of quantitative traits can greatly assist the design of strategies for their manipulation in plant-breeding programs. For a number of traits, genetic variation can be the result of segregation of a few major genes and many polygenes (minor genes). The joint segregation analysis (JSA) is a maximum-likelihood approach for fitting segregation models through the simultaneous use of phenotypic information from multiple generations. Our objective in this paper was to use computer simulation to quantify the power of the JSA method for testing the mixed-inheritance model for quantitative traits when it was applied to the six basic generations: both parents (P₁ and P₂), F₁, F₂, and both backcross generations (B₁ and B₂) derived from crossing the F₁ to each parent. A total of 1968 genetic model-experiment scenarios were considered in the simulation study to quantify the power of the method. Factors that interacted to influence the power of the JSA method to correctly detect genetic models were: (1) whether there were one or two major genes in combination with polygenes, (2) the heritability of the major genes and polygenes, (3) the level of dispersion of the major genes and polygenes between the two parents, and (4) the number of individuals examined in each generation (population size). The greatest levels of power were observed for the genetic models defined with simple inheritance; e.g., the power was greater than 90% for the one major gene model, regardless of the population size and major-gene heritability. Lower levels of power were observed for the genetic models with complex inheritance (major genes and polygenes), low heritability, small population sizes and a large dispersion of favourable genes among the two parents; e.g., the power was less than 5% for the two major-gene model with a heritability value of 0.3 and population sizes of 100 individuals. The JSA methodology was then applied to a previously studied sorghum data-set to investigate the genetic control of the putative drought resistance-trait osmotic adjustment in three crosses. The previous study concluded that there were two major genes segregating for osmotic adjustment in the three crosses. Application of the JSA method resulted in a change in the proposed genetic model. The presence of the two major genes was confirmed with the addition of an unspecified number of polygenes. Received: 18 August 2000 / Accepted: 9 March 2001     

Genetic studies of anther culture ability in rice (Oryza sativa)

Inheritance of three anther and culture characters, callus induction, green plant regeneration and culture efficiency was studied using incomplete diallel crosses with a gamete model. It was suggested that callus induction was mainly controlled by gametic additive effects and with less effect of the maternal effects. Green plant regeneration was mainly determined by maternal effects with less influence of gametic additive effects. Culture efficiency was controlled by gametic additive, maternal and cytoplasmic effects. Cultivar Lunhui 422 showed positive genetic effects for all three traits and was a very good parent for rice anther culture breeding. Significant positive heterosis was observed for callus induction. Both gametic additive and maternal correlations contributed to the significant genotypic and phenotypic correlations between callus induction and green plant regeneration suggesting these two traits to be linked.Abbreviations 2,4-d 2,4-dichlorphenoxyacetic acid - NAA -napthaleneacetic acid     

Quantitative genetics of growth and development in Populus. I. A three-generation comparison of tree architecture during the first 2 years of growth

One approach to gain an insight into the genetics of tree architecture is to make use of morphologically divergent parents and study their segregating progeny in the F₂ and backcross (B₁) generations. This approach was chosen in the present study in which material of a three-generation pedigree growing side by side in a replicated plantation, was analyzed. The pedigree included Populus trichocarpa (T) and P. deltoides (D) parents, their F₁ and F₂ hybrids and their B₁ hybrids to the D parent. The trees were grown in the environment of the T parent and measured for the first 2 years of growth. Nine quantitative traits were studied at the stem, branch and leaf levels of tree architecture, in which the original parents differed. Strong F₁ hybrid vigor relative to the better parent (T) was expressed in growth and its components. Most quantitative traits in the F₂ and B₁ hybrids were intermediate between the T and D parents but displayed a wide range of variation due to segregation. The results from the analysis of variance indicated that all morphometric traits were significantly different among F₂ and B₁ clones, but the B₁ hybrids were more sensitive to replicates than the F₂. Broad-sense heritabilities (H ²) based on clonal means ranged from moderately high to high (0.50–0.90) for the traits studied, with H ² values varying over age. The H ² estimates reflected greater environmental noise in the B₁ than in the F₂, presumably due to the greater proportion of maladaptive D alleles in those hybrids. In both families, sylleptic branch number and length, and leaf size on the terminal, showed strong genetic correlations with stem growth. The large divergence between the two original parents in the traits studied, combined with the high chromosome number in Populus (2n=38), makes this pedigree well suited for the estimation of the number of quantitative trait loci (QTLs) underlying quantitative variation by Wright's biometric method (1968). Variation in several traits was found to be under the control of surprisingly few major QTLs: 3–4 in 2nd-year height and diameter growth, a single QTL in stem diameter/height ratio.     

Reciprocal effects in anther cultures of wheat hybrids

This study was conducted to determine the reciprocal effects for anther culture response in wheat (Triticum aestivum L.) using a set of 4 × 4 full diallel crosses. Both reciprocal and nuclear genetic effects were highly significant for anther culture response and useful for selection and breeding purposes. General combining ability (GCA) effects were predominant for all investigated anther culture traits. Also, significant differences for specific combining ability (SCA) effects were detected between reciprocal crosses. Although significant reciprocal differences for responding anther, callus number and green plant regeneration were recorded in some reciprocal crosses, there were no significant reciprocal differences for albino plant regeneration. The use of one parent as male or female could lead to change at the production of green plants from the F₁ hybrids and screening of inbred lines for response to anther culture, without reciprocal effects, could decrease the utilization of breeding material.     

Heritability estimates for callus growth and regeneration in desmodium

The F₂ and F₃ generations of two crosses (6123×13083 and 6123×144, with 6123 the regenerating parent) were evaluated for callus growth and regeneration capacity. Based on joint scaling tests and variance partitioning, neither callus growth nor regeneration fitted a simple additive-dominant genetic model. Heritability estimates obtained from parent-offspring regression analyses ranged from 0.65 to 0.77 for callus growth and from 0.19 to 0.46 for regeneration, with the range in both influenced by the cross and numerical scale employed. Members of two F₃ families exhibited much more vigorous and prolific regeneration than the regenerating parental genotype. Because many individuals in the segregating generations showed no evidence of regeneration, population distributions for this trait were severely truncated, or censored. Regression-order analysis was used to estimate means and variances of these censored populations. The association between poor callus growth and high regeneration capacity observed in the parental lines was absent from the F₂ and F₃ generations, indicating that no association between callus growth and regeneration was present.     

Plant regeneration from sorghum anther cultures and field evaluation of progeny

Summary Embryogenic calli were obtained from a hybrid line of Sorghum bicolor (L.) Moench anthers with mid to late uninucleate pollen cultured in N₆ medium supplemented with 3.0% sucrose, 2.0 mg/1 2,4-D, 0.8% agar and incubated at 30°C, which was the optimum temperature. The regeneration of embryos was obtained from the embryogenic calli cultured in modified MS medium supplemented with 3.0% sucrose, 2.0 mg/1 BAP combined with 0.3 mg/1 IAA and 0.8% agar. A total of 248 doubled haploids and 12 haploid plants were regenerated. In a subsequent field study, the selfed progeny from anther culture (designated as the anther culture-2, [A₂] generation) derived families was compared with both the F₂ and the F₁ for agronomic and morphological traits. Significant differences were noticed between the family means of both A₂ and F₂ for all the quantitative traits studied. The distinctive difference in the behavior of the A₂ families in comparison with the F₂ was established by within family variance, which was significant in F₂ for days to 50 per cent flowering, plant height, panicle length, leaf area index, dry matter production, harvest index and grain yield and was non-significant in A₂. Male sterility, one of the potentially important traits, currently exploited in the hybrid seed production of cereals, including CSH5 hybrid sorghum and the morphological traits (panicle shape, compactness, grain color, glume color and nature of the leaf sheath) segregated in the F₂. Such segregation was not observed within A₂ families and they bred true to their respective A₁ plants, indicating the rapid attainment of homozygosity/uniformity. The present study establishes the gametophytic origin of anther culture derived families and indicates the possibility of rapid production of homozygous lines which can be used as recombinant inbreds.Abbreviations N₆ Chu et al. (1975) - MS Murashige and Skoog (1962) - 2,4-D, 2 4-Dichlorophenoxyacetic acid - IAA Indole-3 -acetic acid - BAP Benzylaminopurine - A₁ regenerated plants - A2 selfed progeny from A₁     

The Relationship between the Traits of the Two-Row Spike,the High Number of Thillers,and the High Regeneration Capacity in in vitro Culture in Barley

In barley (Hordeum vulgare L.), the traits of the two-row spike, the high rate of plant tillering, and the high capacity for multiple plant regeneration (MPR) in a callus culture of immature embryos were shown to correlate. When a dihaploid line (DH) obtained from cv. Golden Promise (two-row spike, high number of thillers) was crossed to a DH line from cv. Bruce (six-row spike, low number of thillers), the two-row trait dominated the F₁ generation, whereas, in F₂, the segregation ratio was 3 : 1. From F₃ progeny, we isolated the families comprising two-row homo- and heterozygotes and six-row homozygotes. In an F₃ hybrid population, the two-row plants manifested higher tillering and MPR rates as compared to the six-row plants. The correlation between the traits of the two-row spike, the high tillering, and the high MPR capacity may depend on the pleiotropic V gene, which controls the general mechanisms of meristem functioning essential for the development of these three traits.     

Inheritance of flag-leaf angle, flag-leaf area and flag-leaf area duration in four wheat crosses

 Flag-leaf angle (FLAngle), flag-leaf area (FLarea) and flag-leaf area duration (FLADuration) are important traits in determining yield in wheat (Triticum aestivum L). Genetic studies on these traits are very few. The objective of this study was to determine the gene action controlling those traits in four wheat crosses. Six generations were available for each cross: parents (P₁ and P₂), F₁, F₂ and backcrosses (BC_(F1×P1) and BC_(F1×P2)). The joint scaling test described by Mather and Jinks was used to test goodness of fit to eight genetic models. Models including additivity, dominance and interallelic interactions best fitted the data for the three traits and the four crosses. Additive effects were most prevalent for FLAngle. They were also significant for FLArea and FLADuration. Dominance and epistatic gene action were also found, but the degree and direction was both trait- and genotype-specific. Heritabilities values were intermediate. Genetic progress, although slow, can be expected when selecting for these traits; however, selection would be most effective if delayed to later generations because of dominance and epistatic effects. Received: 20 April 1998 / Accepted: 14 July 1998     

Genetic mapping in maize with hybrid progeny across testers and generations: plant height and flowering

DNA markers were used to identify quantitative trait loci (QTLs) for plant height, ear height, and three flowering traits in hybrid progeny of two generations (F_2:3, F_6:8) of lines from a Mo17×H99 maize population. For both generations, testcross (TC) progeny were developed by crossing the lines to three inbred testers (B91, A632, B73). The hybrid progeny from the two generations were evaluated at the same locations but in different years as per an early generation testing program. QTLs were identified within each TC population and for mean testcross (MTC) performance. Overall, more QTLs were detected in the F_6:8 than the F_2:3 generation. Totalled over all five traits, 41 (B91) to 69% (B73) of the QTLs for tester effects and 67% of the QTLs for MTC detected in the F_2:3 generation were verified in the F_6:8 generation. Although differences in relative rank of the QTL effects across generations were observed, especially for the flowering traits, parental contributions were nearly always consistent. Several (8–11) QTLs were identified with effects for all three tester populations and for all traits except the anthesis-silk interval, which had only two such regions. Over all five traits, previous evaluations in this population identified 26 QTLs with consistent effects for two (F_2:3, F_6:8) inbred-progeny evaluations, and 20 (77%) were also associated with MTC in at least one of the generations evaluated herein. In all instances of common inbred and TC QTLs, parental contributions were the same. Received: 26 November 1999 / Accepted: 18 April 2000     

Maximum Likelihood Estimation of Genetic Parameters for Quantitative traits from Autotetraploid Self-Fertilized Populations

Assuming equality of genotypic effects over different loci, this paper provides an ML procedure for estimating genetic parameters for quantitative traits from autotetraploid self-fertilized populations. The results are illustrated by computer generated data involving P₁, P₂, F₂, B₁ and B₂ populations.     

A comparative study of genotypic and environmental response to androgenesis in Nicotiana rustica

Summary A total of six genotypes of Nicotiana rustica comprising the two F₁'s (V₂ × V₁₂ and V₁ × V₅) and their parents were evaluated for their efficiency in haploid production. Excised immature flower buds with pollen at late uninucleate to early binucleate stage were pretreated for 21 days at 5 ° or 7 °C, or for 15 days at 9 °C before culturing on Nitsch's medium+ 0.1 mg/l NAA. The effects of genotype, pretreatment and their interaction were tested on anther response, anther productivity and days to first plantlet formation. Highly significant genotype X pretreatment interaction and differences between genotypes were observed for all three characters. Significant differences between pretreatments were observed for anther productivity only. The performance of V₁₂ both in respect of anther productivity and response was highest whereas that of V₅ was the lowest. Analysis of variance showed that a simple additive genetic model was not adequate to explain the above variation due to significant additive genetic and dominance interactions with the pretreatment.