Inheritance of quantitative traits in crosses between two Pisum sativum subspecies with particular reference to their breeding value

The experimental study was conducted during the period of 2008-2010 at the experimental field of the Institute of Forage Crops in Pleven. The hybridization scheme included direct and back crosses covering four varieties of forage pea (Pisum sativum L.), namely two spring ones, Usatii 90 and Kamerton from Ukraine, and a winter one from Bulgaria, Pleven 10. There was analyzed the inheritance of quantitative traits such as plant height, height to first pod, pod number per plant, seed number per plant, seed number per pod, seed weight per plant and number of fertile nodes per plant of parental components (P1 and P2) and both first (F1) and second (F2) hybrid generations. The cross Usatii 90 x Pleven 10 showed the highest real heterosis effect for plant height (8.26%), pods per plant (158.79%), seeds per plant (272.16%), seeds per pod (42.09%), seed weight per plant (432.43%) and number of fertile nodes per plant (117.14%). The cross Pleven 10 x Usatii 90 had the highest real heterosis effect height to first pod (11.06%). In F2 plants, the strongest depression for plant height (5.88%), seeds per plant (57.88%), seeds per pod (55.93%) and seed weight per plant (55.99%) was in the cross Usatii 90 x Pleven 10, for height to first pod (1.47%) in the cross Kamerton x Pleven 10 and for number of fertile nodes per plant (15.91%) in the cross Pleven 10 x Usatii 90. The highest positive degree of transgression for number of fertile nodes per plant (165.64%) and seed weight per plant (162.10%) was in the cross Pleven 10 x Kamerton and for pod number per plant (102.54%) and seeds per plant (99.13%) in Kamerton x Pleven 10. The stability of the characters was determined. Low variability in F1 and F2 was found in plant height (3.97-6.85%). Variability of number seeds per plant in F1 was highest (11.86-33.23%). For all other traits, the variability varied from average to high. A lower narrow-sense heritability coefficient was observed for plant height, height to first pod, pods per plant, seeds per plant and seed weight per plant (from 0.001 to 0.230). In few cases, such as in fertile nodes per plant (0.39 and 0.81) and seeds per pod (0.44), the coefficients ofbroad-sense heritability were higher.     

Genetic analyses of agronomic and seed quality traits of synthetic oilseedBrassica napus produced from interspecific hybridization ofB. campestris andB. oleracea

The heritability, the number of segregating genes and the type of gene interaction of nine agronomic traits were analysed based on F₂ populations of synthetic oilseedBrassica napus produced from interspecific hybridization ofB. campestris andB. oleracea through ovary culture. The nine traits—plant height, stem width, number of branches, length of main raceme, number of pods per plant, number of seeds per pod, length of pod, seed weight per plant and 1000-seed weight—had heritabilities of 0.927, 0.215, 0.172, 0.381, 0.360, 0.972, 0.952, 0.516 and 0.987 respectively, while the mean numbers of controlling genes for these characters were 7.4, 10.4, 9.9, 12.9, 11.5, 21.7, 20.5, 19.8 and 6.4 respectively. According to estimated coefficients of skewness and kurtosis of the traits tested, no significant gene interaction was found for plant height, stem width, number of branches, length of main raceme, number of seeds per pod and 1000-seed weight. Seed yield per plant is an important target for oilseed production. In partial correlation analysis, number of pods per plant, number of seeds per pod and 1000-seed weight were positively correlated with seed yield per plant. On the other hand, length of pod was negatively correlated (r = -0.69) with seed yield per plant. Other agronomic characters had no significant correlation to seed yield per plant. In this experiment, the linear regressions of seed yield per plant and other agronomic traits were also analysed. The linear regression equation wasy = 0.074x₈ + 1.819x₉ + 6.72x₁₂ -60.78 (R ² = 0.993), wherex ₈, x₉ and x₁₂ represent number of pods per plant, number of seeds per pod and 1000-seed weight respectively. The experiment also showed that erucic acid and oil contents of seeds from F₂ plants were lower than those of their maternal parents. However, glucosinolate content was higher than that of the maternal plants. As for protein content, similar results were found in the F₂ plants and their maternal parents. It was shown that the four quality traits, i.e. erucic acid, glucosinolate, oil content, and protein content, had heritability values of 0.614, 0.405, 0.153 and 0.680 respectively.     

Density Studies on Lupins. II. Components of Seed Yield

Components of seed yield of cv. Ultra (Lupinus albus L.) andcv. Unicrop (L. angustifolius L.) were measured when grown atthree densities. The low density (10 plants m^–2) Unicropyield (34 g seed per plant) was 1.8 times that of Ultra as ithad more branches, pods and seeds per pod. Ultra seeds (310mg per seed) were heavier than Unicrop seeds (180 mg). The branchingpattern of Ultra was less dependent on plant density, henceat 93 plants m^–2 it gave a higher per plant yield (7.4vs 6.4 g) than Unicrop at lower densities (83 plants m^–2).Density had most influence on pod formation and only small effectson seeds per pod and seed weight. Yield components on the main-steminflorescence were influenced less by density than componentson branch inflorescences. Later formed, higher order generationsof inflorescences were most affected by increased inter- andintra-plant competition. Pod numbers on the main-stem were similarfor both species. Pods formed at higher flower nodes in Unicrop,but the lower flower nodes were less fertile than those in Ultra.Node position of flowers had no influence on seed set in main-stemUnicrop pods, but pods from higher nodes in Ultra formed fewerseeds. Seed weights in Unicrop were similar among main-stemnodes but in Ultra seed weights tended to increase at highernodes. Lupinus spp, lupins, seed yield, planting density     

Introgression of the reduced height gene <Emphasis Type="Italic">Rht10</Emphasis> from the wheat cultivar Ai-Bian 1 into the triticale genotype

A gene determining reduced height, Rht10, from the wheat cultivar Ai-Bian 1 was introgressed into the triticale genotype. Initially, Ai-Bian 1 was crossed with the wheat cultivar Chinese Spring (CS), a carrier of Kr genes, to overcome the uncrossability of this cultivar with rye. Amphidiploids were produced by hybridizing the F₂ (CS × Ai-Bian 1) plants displaying reduced height (at the level of Ai-Bian 1) with rye. Free pollination of F₁ (F₂ of CS × Ai-Bian 1) × Saratovskaya 7 with triticale pollen gave fertile viable hybrids; the majority of hybrids were phenotypically closer to octoploid triticale; however, the variants intermediate between octo-and hexaploids were also present. The height of amphidiploids varied from 40 to 90 cm, and the grain yield per spike amounted on the average to 11.7–24.7 grains, which exceeded essentially this value in F₁ plants.     

REPRODUCTIVE ISOLATION BARRIERS TO GENE EXCHANGE BETWEEN SOLANUM CHACOENSE AND S. COMMERSONII (SOLANACEAE)

In contrast to the general intercompatibility of diploid species of tuber-bearing potatoes of South America, Solanum chacoense Bitter and S. commersonii Dunal have well-established internal barriers to gene exchange. Pollen tubes of S. commersonii are inhibited in growth down the style of S. chacoense. While S. chacoense pollen tubes are not inhibited in S. commersonii stylar tissue, seed development is abnormal, resulting in production of large numbers of seeds that are not filled out. Even the apparently normal F₁ seed germinated poorly; approximately 0.1 germinable seeds were set per cross as compared with over 30 seeds per cross following intraspecific crosses. Lowland S. chacoense, including populations sympatric with S. commersonii, were not more effectively isolated from S. commersonii than were highland S. chacoense populations, over 500 km from the nearest S. commersonii. The F₁ hybrids produced were vigorous and highly fertile. Crosses between unrelated S. commersonii-chacoense F₁ hybrids produced only 1.3 germinable seeds per cross. This reduction resulted from low numbers of berries set, few seeds per berry, and low seed germination. The F₂ progeny were vigorous, but while many were both male and female fertile there were indications of an increase in sterility over that of the parents and F₁'s. The data were interpreted as indicating that the isolation barriers result from polygenic differences between the parent species and are composed principally of genes that function in several of the processes of seed setting. The accumulation of genes that keep these species isolated was interpreted as not having developed as a result of selection for such isolation in the region of overlap (Wallace effect), but rather as a byproduct of divergence that occurred during their allopatric evolution.     

RECIPROCAL DIFFERENCES IN INTRASPECIFIC CROSSES OF TOBACCO RESULT FROM EMBRYO DEATH

Tetraploid tobacco plants (Nicotiana tabacum) derived from cultured cell lines (TC) are partially cross-incompatible with their diploid progenitors (C). C × TC crosses (TC-derived tetraploids as the pollen parent) yield only 2% viable seed. The remaining seeds are normal size but lack an embryo (apoembryonic seeds). Apoembryonic seeds do not occur in the reciprocal TC × C crosses. Sections of ovules from C × TC crosses revealed that an embryo formed but that embryo growth slowed at 5 days postpollination and that by the 12th day following pollination, the embryo had disappeared although the ovule continued to develop. Endosperm degeneration occurred concurrently with embryo death. Culturing ovules from C × TC crosses has increased the yield of F₁ plants from 2% to as much as 25% indicating that embryo rescue is possible. Surviving F₁ plants from TC × C crosses have close to triploid chromosome numbers and are fertile.     

REPRODUCTIVE CAPACITY AND SEED SIZE IN LUPINUS TEXENSIS

The average number of ovules produced per individual of Lupinus texensis is much greater than the average number of seeds per plant. Each plant produces approximately 2,000 ovules but only 2.5% develop into seeds. One fourth of the seeds is lost due to abortion and 0.3% is lost due to predation on the plant. Mature seeds from this population exhibit a five-fold range in weight, from 10 to 56 mg. The distribution of seed weights in the field population is skewed and leptokurtic. Seed wt is positively correlated with both seed germination and seedling survivorship. Heritability of seed wt is 0.09. There is no correlation between average seed wt per plant and total number of seeds per plant, seeds per pod, or legumes per plant.     

太空诱变玉米核不育突变体矮化的遗传及外施赤霉素分析

为了解太空诱变玉米核不育突变体矮化的遗传规律和原因,该研究以不育突变体为母本,自交系178、478为父本,对测交 F1、F2群体进行育性鉴定和株高分析,对 F2可育株进行基因型和株高分析,对姊妹交后代分离群体进行育性鉴定和株高、雄穗长度、节间数、节间长度分析,同时,还对姊妹交后代分离群体进行施赤霉素处理,调查育性和株高的变化。结果表明：178和478背景下的 F1表现出与测交母本一样的极显著差异;在178和478核背景下的 F2中,不育株株高极显著矮于可育株,两核背景下的不育株间株高差异不显著,而可育株间株高差异极显著;F2中纯合和杂合可育株的株高差异不显著;姊妹交后代分离群体中不育株株高、雄穗长度、节间数和节间长度极显著小于可育株;外施赤霉素的不育株在苗期表现出对赤霉素一定的敏感性,但株高最终未恢复正常高度。因此,得出该突变体矮化表现稳定,与不育性状并存,且不受细胞核背景的影响;核不育基因对植株株高的矮化无剂量效应;突变体的矮化与雄穗长度、节间数和节间长度有关;突变体不完全属于赤霉素不敏感型,其矮化并不是单一缺乏赤霉素而引起。该研究结果为认识太空诱变玉米核不育突变体矮化的遗传和生理机制提供了参考。     

Genetic analysis of agronomic characters in chickpea

Summary Twenty-eight diallel trials over 8 years and two locations were analysed to estimate genetic variances for agronomic characters of chickpea (Cicer arietinum L.). The data were analysed according to Method 4 and Model I of Griffing (1956). Days to flowering, plant height, and seed size were found to be predominantly under additive inheritance and were highly predictable. Both additive and non-additive genetic components were important for seed yield, number of branches, pods per plant, and seeds per pod. Although both general combining ability (gca) and specific combining ability (sca) varied significantly with generation, components of gca mean squares were invariably much larger than gca x generation interaction components, indicating that either the F₁ or the F₂ generation can be used to estimate the gca components effectively. Combined diallel analysis of F₂s over locations revealed the importance of combining ability x location interactions and emphasized the need for testing over more than one location for the precise estimation of combining ability. The implications of these findings and those reported earlier in the literature on the breeding strategies/methods for the genetic improvement of agronomic characters in chickpea are discussed.ICRISAT journal article no. 1199     

Assessment of inheritance pattern and agronomic performance of transgenic rapeseed having harpin<Subscript>Xooc</Subscript>-encoding <Emphasis Type="Italic">hrf2</Emphasis> Gene

hrf2 gene is a member of the harpin-encoding gene family of rice-pathogenic bacterium Xanthomonas oryzae pv. oryzicola. In our previous studies, we observed that harpin_Xooc could elicit hypersensitive cell death in non-host plants, induce disease and insect resistance in plants, and enhance plant growth. In this study, the rapeseed cultivar, Yangyou 4, was genetically engineered via Agrobacterium-mediated transformation to express the hrf2 gene. Polymerase chain reaction (PCR) and southern blot analyses of T₁ generation of transgenic rapeseed revealed stable integration and expression of the inserted gene hrf2. In addition, the resistance to Sclerotinia sclerotiorum was greatly enhanced. A comparison between agronomic characters of transgenic and control lines displayed significant differences in terms of plant height, stem width, number of pods per plant, number of seeds per pod, 1,000-seed weight, and seed yield per plant. Among lines with resistance to S. sclerotiorum, T₁1 had improved agronomic traits compared with controls with a 22.7% seed yield increase. These results suggest that the introduction of the hrf2 gene into rapeseed can be an effective strategy for enhancing resistance to S. sclerotiorum.     

Increased pre-dispersal seed predation in sunflower crop-wild hybrids

The fitness of crop-wild hybrids can influence gene flow between crop and wild populations. Seed predation levels in crop-wild hybrid plants can be an important factor in determining plant fitness, especially in large-seeded crops such as sunflower. To determine patterns of pre-dispersal seed predation, seeds were collected from wild sunflowers (Helianthus annuus L.) and wild×crop F₁ hybrids at three experimental field sites in eastern Kansas. Seed heads were dissected and each seed was counted and scored for categories of seed damage by lepidopteran and coleopteran larvae. Hybrid seed heads showed significantly higher levels of insect-damaged seeds. The average hybrid plant had 36.5% of its seeds (or 45.1 seeds per plant) eaten by insect larvae while the average wild plant lost only 1.8% (or 95 seeds) to seed predators. Hybrid populations had higher levels of total insect damage even when date of flowering, flower head diameter, and the number of open heads within the study site were accounted for. These results suggest that the reduced fecundity of F₁ crop-wild sunflower hybrids demonstrated in other studies may be augmented by the increased seed predation in hybrid flower heads. Fecundity estimates of crop-wild hybrid and wild plants that disregard differential seed predation levels may not accurately reflect the actual relative contributions of hybrid and wild plants to future generations. Received: 21 December 1998 / Accepted: 8 July 1999     

Intensity of pre‐dispersal seed predation in the invasive legume Leucaena leucocephala is limited by the duration of pod retention

Abstract The intensity of seed predation the invasive tropical legume Leucaena leucocephala by the bruchid Acanthoscelides macropthalmus was investigated in south‐eastern Queensland, Australia. The number of seeds damaged by A. macropthalmus as a proportion of total seeds available was found to increase the longer the pods remained on the tree. Seed predation ranged from a mean of 10.75% of seeds on pods that remained on the plant for 1 month and increased to 53.54% for pods that remained of the plant for 4 months. The low bruchid populations at high pod densities results in ‘predator satiation’. However, pods dehisce over time and the proportion of pods available over time to the bruchid correspondingly declines. By the time bruchid densities build up, most pods have dehisced and the seeds consequently escape predation. As a result the number of seeds lost to bruchid damage increases only marginally over time. Despite the levels of seed predation observed over the course of the study, the number of seeds in the soil seedbank almost doubled over time increasing from 8.5 seeds m^?3 to 15.5 seeds m^?3 over a 4‐month period. Levels of seed predation and addition of seeds to the soil seedbank were not correlated. The taxonomic (subspecies) status and apparency of host plants as measured by plant and patch traits (average plant height, density of podding plants and patch size) did not influence levels of seed predation. Pre‐dispersal seed predation studies need to take into account the pod/seed retention behaviour of the plant. The ability of the bruchid to regulate the invasiveness of Leucaena through influencing its demography is likely to be diminished if the insect populations cannot increase rapidly enough to use the seeds before pod dehiscence.     

Unraveling the inheritance pattern of yield and associated traits in Rapeseed (<Emphasis Type="Italic">Brassica napus</Emphasis> L.)

In this study, 56 F₁ crosses of B. napus, including their eight parents, were developed through complete diallel mating design. Analysis of variances (ANOVA) of combining ability showed very highly significant (P ≤ 0.01) values for the general combining (GCA), specific combining (SCA) and the reciprocal combining ability (RCA) towards yield and its associated traits. Parental lines, AUP-9 (3.51), AUP-18 (37.26), AUP-20 (0.12), AUP-7 (0.11), and AUP-18 (5.66), were found as the best general combiners for each of the traits: pods on main raceme, pods on individual plant, seeds on each pod, 1000 seed weight and seed yield plant^?1, respectively, whereas, based on desirable SCA effects, crosses found best were AUP-14 × AUP-18, AUP-14 × AUP-20, AUP-8 × AUP-20, AUP-2 × AUP-18, AUP-2 × AUP-14, and AUP-2 × AUP-9 for pods main raceme^?1, pods plant^?1, seeds pod^?1, 1000 seed weight and seed yield plant^?1, respectively. Superior reciprocal hybrids for economically important traits such as pods main raceme^?1, pods plant^?1, seeds pod^?1, and seed yield plant^?1 were AUP-17 × AUP-9, AUP-14 × AUP-2, AUP-18 × AUP-7 and AUP-20 × AUP-8, respectively, involving at least one best general combiner (parental line). Estimates of combining ability variances and predictability ratio (σ ²GCA/σ ²SCA <1.00) revealed the preponderance of a non-additive gene action and was further confirmed by higher values of variances due to SCA than GCA.     

Mating system and seed variation of <Emphasis Type="Italic">Acacia</Emphasis> hybrid (<Emphasis Type="Italic">A. mangium</Emphasis> × <Emphasis Type="Italic">A. auriculiformis</Emphasis>)

The mating system and seed variation of Acacia hybrid (A. mangium × A. auriculiformis) were studied using allozymes and random amplified polymorphic DNA (RAPD) markers, respectively. Multi-locus outcrossing rate estimations indicated that the hybrid was predominantly outcrossed (mean±s.e. t _m = 0.86±0.01). Seed variation was investigated using 35 polymorphic RAPD fragments. An analysis of molecular variance (AMOVA) revealed the highest genetic variation among seeds within a pod (66%–70%), followed by among pods within inflorescence (29%–37%), and the least variation among inflorescences within tree (<1%). In addition, two to four RAPD profiles could be detected among seeds within pod. Therefore, the results suggest that a maximum of four seeds per pod could be sampled for the establishment of a mapping population for further studies.     

Correlations and heritability of the characters determining the seed yield of the long-raceme alfalfa (Medicago sativa L.)

Phenotypic correlation coefficients and heritability of the characters controlling seed yield of long-raceme forms of alfalfa was determined. It was found that seed yield per plant, which was positively correlated with 10 out of 12 analysed characters, depended upon the number of pods per raceme and the number of seeds per pod. Variability of these characters determined about 60% of the variability of seed yield. Multiple linear regression and phenotypic correlations show that simultaneous selection for increased pod number per raceme and increased seed number per pod and raceme length resulted in enhanced seed yield potential. The share of the additive genetic effects in the phenotypic variance for number of pods per raceme was low and about 21-23%, while for number of seeds per pod and per raceme amounted to about 50%. The expected genetic progress in recombination breeding for number of seeds per pod and number of seeds per raceme will be of medium magnitude, while one cannot expect any rapid and considerable progress in the number of pods per raceme. Considering the high positive correlation between raceme length and number of pods and seeds per raceme, one should conclude that raceme length can be an important criterion in selection of plants showing a high seed productivity.     

Diversity of pea (Pisum sativum) accessions based on morphological data for sustainable field pea breeding in Argentina

We characterized 13 accessions of dry peas of different origins from various growing regions in Argentina, based on three replications of 20 plants cultivated in 2009 and 2010 in a greenhouse, with the objective of selecting those with favorable characteristics for use in breeding programs. Significant differences were found for length and width of stipule and pod, length of the internodes and leaflets, plant height, total number of nodes, number of nodes at the first pod, number of days to flowering and to harvest, number of pods and seeds per pod, 100-seed weight and grain diameter, demonstrating a high degree of genetic variability. Phenotypic correlation analysis demonstrated that large pods produced more seeds per pod, but the seed weight decreased. Plants with smaller number of nodes in the first pod were more productive. Estimates of genotypic correlation coefficients indicated a strong inherent association among the different traits. Clustering methods grouped the accessions into five clusters. Cluster 5 included two accessions and showed the highest values for length and width of stipules (4.9 and 4.5 cm, respectively), length of leaflets (7.43 cm) and days to flowering (122.6), while cluster 3, with one accession, and cluster 4, with two accessions, showed the highest values for number of seeds per pod (3.78 and 4.39), number of pods per plant (5.33 and 5.70), length of pods (5.54 and 5.72 cm), and width of pods (1.21 and 1.20 cm, respectively). We conclude that accessions in clusters 3 and 4 would be useful for crosses with other cultivars in pea breeding programs.     

Efficiency of early generation selections for yield and related characters in safflower (Carthamus tinctorius L.)

The efficiency of early generation selection for yield and related characters in safflower (Carthamus tinctorius L.) was studied in the F₂, F₃ and F₄ generations. Twenty-five F₂ progenies derived from various crosses were studied. In the F₂ generation, number of capitula per plant (CNSP), number of seeds per capitulum (SPSP), test weight (SWSP), and seed yield (SYSP) were the criteria used for single plant selection. The analysis of variance showed significant differences for all of the characters in the F₂, F₃, and F₄ generations. The analysis of variance in each of the selection classes showed highly significant genotypic differences. A large number of selections in the CNSP and SYSP classes showed greater yield than the check variety. In each class the mean for that particular character showed a positive shift. The observed F₃ and F₄ means for seed yield per plant was higher in SYSP, indicating the effectiveness of single plant selection for yield. Correlated response showed that selection for number of capitula per plant was effective for improvement of yield.     

Regulation of Leaf Senescence by Reproductive Sink Intensity in Cowpea (Vigna unguiculata L. Walp)

The relationship between seed number per pod and senescenceof the leaf in its axil was examined in a determinate cowpea(Vigna unguiculata L. Walp) variety C.779. The seed number perpod was reduced at all fruiting nodes by surgical excision ofpart of the 4-d-old pod. Leaf senescence as measured by lossof leaf area, chlorophyll content and soluble protein was sloweddown in leaves supporting the development of an artificiallyreduced number of seeds. Diminished nitrogen mobilization fromthe leaf could not account for the reduced rate of leaf senescence.The result suggests the involvement of a senescence signal fromthe developing seeds to the leaf in its axil. Development ofthe basal half of the excised pod in the cowpea provides a uniquesystem for manipulating seed number per pod. Senescence, monocarpic, chlorophyll, protein, Vigna unguiculata, cowpea     

Characterization of backcross generations obtained under field conditions from oilseed rape-wild radish F1 interspecific hybrids: an assessment of transgene dispersal

Gene flow from glufosinate-resistant transgenic oilseed rape to wild radish was studied over two backcross generations. Under field conditions,?seed production from oilseed rape-wild radish F₁ hybrids due to pollination by wild radish was always low: on average 0.12 and 0.78 seeds per 100 flowers and per plant, respectively. The cytogenetics of the resulting «BC₁» plants can be explained in the main by three different genomic constitutions: either ACRrRr, 2n=37, ACRr, 2n=28 (the same chromosome number as the mother plant), or by the amphidiploid AACCRrRr, 2n=56. The probability of gene exchange through chromosome pairing was high only in plants with 2n=28 or 37 chromosomes. Due to the viability of unreduced or partially reduced female gametes, most of the «BC₁» plants (81.9%) were Basta resistant whereas the analysis of oilseed rape specific loci indicated that their transmission varied with the locus. In spite of low male fertility (8.7%), an improvement of the female fertility over the F₁ hybrids was observed with an average production of 1.4 and 11 seeds per 100 flowers and per plant, respectively. At the following «BC₂» generation, the bar gene transmission (57.2% of Basta-resistant plants) decreased as did the chromosome number, with a majority of plants having between 24 and 27 chromosomes, with 10.5% similar to wild radish (2n=18). The lower the chromosome number, the better the fertility of the «BC₂» plants. On average, 7.9 and 229.3 seeds per 100 flowers and per plant were produced. Gene-flow assessment is discussed based on these data.     

Prospects for interspecific hybridization of Lupinus atlanticus Gladst. with L. cosentinii Guss.

Summary Successful crossing is reported between L. atlanticus Gladst. (2n = 38) and L. cosentinii Guss. (2n = 32), using lines of both species selected for crossability followed by selection of relatively fertile progenies. In one cross, 82E75, from a single F₂ segregating plant, 22 F₃ seeds were obtained. Some other less crossable combinations were completely sterile in the f₁ or F₂. Backcrossing to both parent species was successful, but some crosses gave relatively more seed by using F₂ plants for backcrossing rather than F₂'s. It is concluded that potential exists for introgression of useful genes in both directions.