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.     

Inheritance of quantitative traits in crosses between two <Emphasis Type="Italic">Pisum sativum</Emphasis> 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 × 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 × 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 × Pleven 10, for height to first pod (1.47%) in the cross Kamerton × Pleven 10 and for number of fertile nodes per plant (15.91%) in the cross Pleven 10 × 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 × Kamerton and for pod number per plant (102.54%) and seeds per plant (99.13%) in Kamerton × 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 of broad-sense heritability were higher.     

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.     

Morphological development of normal and phyllody expressing Rosa hybrida cv. Motrea flowers

A large number of soybean (Glycine max L. Merr.)flowers and young pods abscise rather than develop into mature pods. Flower andpod drop or abortion accounts for the majority of total reproductive abscissionand influences potential soybean yield. The objectives of this study were todetermine the patterns of flower, pod and seed development under treatmentswiththe growth regulators, 2-(2,4-dichlorophenoxy) propanoic acid (2,4-DP) and6-benzylaminopurine (BAP), applied at the early reproductive stages, and toexamine the association of reproductive abscission with growth characteristicsand agronomic traits, including seed yield and seed weight. Small seeded [cvPungsan (11.1±0.4 g100-seed^–1)] and large seeded [cv Manlee(21.0±0.5 g 100-seed^–1)]genotypes were separately planted in the greenhouse and field, and treated witheither 2,4-DP or BAP. 2,4-DP (a synthetic auxin) and BAP (a syntheticcytokinin)were each applied at three concentrations (i.e. high, intermediate or low):0.12mM, 0.08 mM, 0.04 mM, and 1.5mM, 1 mM, 0.5 mM respectively. High andlow concentrations were employed for greenhouse experiments to examine thenumber of flowers per plant in pots. With the exception of low BAP (0.5mM) treatment in Pungsan, all treatments increased total podnumberwith various numbers of seeds per pod. Low 2,4-DP (0.04 mM) inbothgenotypes or BAP (0.5 mM) in Manlee significantly reduced flowerabortion and delayed abscission of pods in both genotypes, resulting inincreased pod setting rates. Under field conditions using intermediateconcentrations, 1 mM BAP significantly increased 100-seed weightto22.3 g at R1 in Manlee and 11.9 g at R3 in Pungsan.BAP (1 mM) at R3 in Pungsan significantly improved seed yield(40.1g plant^–1). Maturity was not significantlyaffected by either application in Manlee, but was significantly affected by BAPin Pungsan. In Pungsan, 2,4-DP increased pod number, plant height and nodenumber, but decreased 100-seed weight in Pungsan treated at R1, causing nosignificant change of seed yield. This study suggested that exogenousregulatorssignificantly influenced reproductive and growth characteristics, andconsequently seed yield, but increase of pod number was not always beneficialfor seed yield.     

大豆滞绿(stay-green)突变体诱变后代表型性状变异分析

本文利用大豆滞绿突变体Z-94320经60Co-γ射线诱变的突变体后代M5、M6代为材料,进行两年的田间性状观察记录统计,用相关性分析、主成分分析、聚类分析对其17个主要表型性状统计分析。结果表明:诱变后代产生了丰富的变异,出现了多种种皮色和子叶色,产生了非滞绿性状,形成了各种生育周期,且分离出晚熟性状。通过相关性分析发现,单株粒重与株重、茎粗、主茎荚数、分枝荚数、一粒荚数、二粒荚数、三粒荚数、瘪粒荚数、虫食数呈极显著正相关,这些性状可以对产量进行预测;主成分分析在M5代提取出“产量因子”、“株型因子”、“粒荚因子”、“茎荚因子”四个主成分,对农艺性状累计贡献率达到70.50%,M6代提取出“产量因子”、“虫害因子”、“株型因子”、“茎杆因子”四个主成分,对农艺性状累计贡献率达到71.54%;聚类分析将M5、M6代材料分别划分为6类,发现同代中各类群农艺性状情况大致相似,但是各农艺性状在两代之间的变化明显,在株重、结荚高度、单株粒重等方面M6代显著高于M5代,并筛选出两株高产品系和一株特色滞绿品系。本研究逐步完善了对滞绿大豆突变体库的构建,为滞绿大豆诱变后代的遗传多样性研究提供了基础的数据分析。     

A 9 × 9 diallel analysis in peanuts (A. hypogaea L.): Flowering time,tops' weight,pod yield per plant and pod weight

Summary Four quantitative traits were studied by analysing F₂ data derived from a 9 × 9 diallel cross utilizing widely divergent, inbred, erect cultivars of peanuts, A. hypogaea. Bidirectional dominance was found in the traits total pod yield per plant and number of days from planting to first flower; in pod size, the alleles giving small pods were consistently dominant and for high tops' weight, dominance and overdominance were found. The high heritability of pod yield/plant (0.79) indicates that breeding for higher yield/plant can succeed if large F₂ populations are grown and rigorous visual selection combined with progeny testing are employed. The genetic correlations of pod yield/plant with other traits were low. Breeding for plants with large (jumbo) pods can be aided by the fact that they are homozygous recessive, or nearly so. Simultaneous breeding for high yields and large pods is possible: there was a positive (but low) genetic correlation between the two (0.16). A modification by which less biased estimates of the number of effective factors can be obtained and a possible relationship between bidirectional dominance and genic interaction were proposed.     

Diversity in greengram (Vigna radiata (L.) Wilczek) germplasm collection and its potential use in crop improvement

Greengram or mungbean (Vigna radiata (L.) Wilczek), which originated in the Indian sub-continent, is an important pulse crop in India. Genetic diversity and patterns of variation among 111 accessions representing the better agronomic types from the entire collection of the National Bureau of Plant Genetic Resources were studied. Wide variation in morphological and agronomic traits viz. number of pods per plant, yield per plant, 100-seed weight, fruit setting capacity, flowering period, maturity, number of pod bearing peduncles, plant height, number of primary branches, length of branch, nodulation and leafiness was observed. Grain yield was found to be significantly correlated with 100-seed weight and pod length. The data were subjected to cluster and principal components analysis. The accessions were grouped into six discrete and well-defined clusters. The study demonstrated the patterns of variation at the population level. The multivariate analysis was useful in identifying a group of accessions with yield enhancing traits within a highly diverse group of accessions and their potential value in greengram improvement is suggested.     

Genetic basis of variation of yield, and yield components in mungbean (Vigna radiata (L.) Wilczek)

Additive, dominance, and epistasis genetic basis of seed yield per plant, number of pods per plant, number of seeds per pod, and 1000 seed weight in mungbean (Vigna radiata (L.) Wilczek) have been examined, using Triple Test Cross (TTC) analysis. The material for TTC test was evaluated in two seasons i.e., kharif (July-October) and spring/summer (March-June), at the research station of the Nuclear Institute for Agriculture and Biology (NIAB), Faisalabad, Pakistan. Epistasis was present significantly for number of pods per plant and number of seeds per pod when grown in the spring/summer season (March to June). Partition of epistasis showed that additive x additive ('i' type) interaction was an important component of number of pods per plant, and number of seeds per pod was found to be of both types 'i' type, and additive x dominance, and dominance x dominance ('j' and 'l' type) interactions. This indicated that epistasis might be a non-trivial factor in the inheritance of pods per plant, and seeds per pod in mungbean. The expression of epistasis was influenced differentially by particular genotypes, indicating that a limited number of genotypes may not be sufficient to detect non-allelic interactions for a trait in mungbean. Additive and dominance genetic components were significant for all four traits in kharif season (July to October) but only for seed yield and 1000 seed weight in spring/summer season. This suggests that the genes controlling seed yield per plant, and 1000 seed weight are equally sensitive to the environment. The predominance additive gene action in those traits is not significantly influenced by epistasis, suggesting that improvement of the traits can be achieved through standard selection procedures.     

星油藤蒴果及种子的性状变异研究

为进行星油藤(Plukenetia volubilis L.)良种选育,对其蒴果和种子的性状变异进行了研究。结果表明,星油藤蒴果中4、5、6裂片果分别为49.71%、37.69%和12.60%,以4和5裂片为主;种子性状变异系数比果实的小,种子性状比果实更稳定。按果裂片类型统计,以4裂片的性状变异系数最小,性状也较为稳定,性状分化变异率有54.19%~95.63%来自蒴果间,而果实和种子性状分化变异率分别有79.81%~95.76%和67.66%~93.0%来源于裂片类型,性状分化变异受裂片数影响大,而相同裂片数不同蒴果间的变异程度低。不同裂片类型的果实与种子大多数性状间均存在显著或极显著差异,果裂数是造成性状差异的主要原因。种子萌发率以6裂片果5裂片果4裂片果,平均萌发率超过91%;种子萌发率与单果重、单果重与果形态指标、种子重与种子形态性状间均存在极显著正相关关系,其中单果重对果厚、种子重对种子宽的影响大于其它性状。综合分析星油藤以4裂片果的生物产量最高,平均果重和种子重均好于其他类型。     

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     

Characterization of agronomic traits and markers of recombinant inbred lines from intra- and interracial populations of Phaseolus vulgaris L.

The value of intra- and interracial populations in common bean (Phaseolus vulgaris L.) needs to be determined in order to create useful genetic variation for maximizing gains from selection, broadening the genetic base of commercial cultivars, and making efficient use of available resources. Five large-seeded parents of race Nueva Granada (N), two small-seeded race Mesoamerica (M), and one medium-seeded race Durango (D) were hybridized to produce one intraracial (N x N) and three interracial (two N x M and one N x D) populations. Seventy-nine F₂-derived F₆ lines randomly taken from each population along with their parents were evaluated for agronomic traits and markers at Palmira and Popayán, Colombia, in 1990 and 1991. Variation for agronomic traits and for morphological, protein, and isozyme markers was larger in interracial populations than in the intraracial population. Mean seed yield of all lines as well as yield of the highest yielding line from two interracial populations were significantly higher than that of the intraracial population. The highest ( 0.80±0.15) heritability was recorded for 100-seed weight. Values for seed yield varied from 0.19±0.17 to 0.50±0.16. Gains from selection (at 20% selection pressure) for seed yield ranged from 3.9% to 11.4%. Seed yield was positively associated with biomass yield, pods/m², and days to maturity, but harvest index showed negative correlations with these traits and a positive value with 100-seed weight. Polymorphism was recorded for phaseolin, lectins, protein Group-1 and protein Group-2 fractions, and six isozyme loci. Lines with indeterminate growth habit had significantly (P < 0.01) higher seed yield than lines with determinate growth habit in a Redkloud x MAM 4 population. Also, 23 other associations of markers with agronomic traits other than seed yield were recorded. Of these associations, lines with T phaseolin, the Diap1 ² allele, and lilac flower color tended to possess greater seed weight.     

Interactive effect of cytokinin and potassium on sink-source relationships in Lupinus angustifolius

This study examined whether increased K supply in conjunction with BAPcould increase lupin seed yield and harvest index by enlarging sink volume (podnumber), increasing assimilate and improving assimilate partitioning to filltheadditional pods induced by BAP treatment. Narrow-leafed lupin(Lupinusangustifolius, cv. Danja abs^– mutant) was grown inaglasshouse, in pots containing sandy soil with four K treatments (0, 15, 60 and120 mg K/kg soil). BAP (2 mM) was applied daily toallmain stem flowers throughout the life of each flower from opening to senesced.BAP application did not affect assimilate production (as measured by totalabove-ground biomass), but changed assimilate partitioning. On BAP-treatedplants, there were greater proportions of seed to pod wall dry weight on themain stem but smaller proportions on the branches, and an increased weightratioof seed to pod wall overall which meant more assimilate was used for seedgrowthrather than pod wall growth. BAP increased the number of pods per plant by35% and this more than compensated for the decreases in seeds per podandseed weight. Therefore, there was an increased harvest index (+11%)and seed yield per plant (+13%) in BAP-treated plants. BAP alsoincreased the number of pods with filled seeds (146%) on the main stemand main stem seed K⁺ concentration (from 0.81% to0.87%). Added K increased biomass but only slightly affected assimilatepartitioning. As applied K increased, relatively more assimilate was used forpod wall growth rather than seed growth. Added K increased seed yield per plantby about 14% due to increases in seed weight and the number of pods onthe main stem. Moreover, K⁺ concentration in seeds and shootsincreased with increasing level of applied K. Seed yield was enhanced more byBAP when K was supplied at high levels. Increasing K supply interactedpositively with added BAP by increasing narrow-leaf lupin seed yield andharvestindex through increases in assimilate supply and its partitioning into seeds.     

Genetic analysis of agronomic characters in chickpea. II. Estimates of genetic variances from line × tester mating designs

Summary Thirty line x tester experiments involving diverse chickpea (Cicer arietinum L.) germplasm were conducted over 8 years and three locations to determine the nature of the genetic variance for grain yield and related characters, and the effects of generation and environment on these genetic parameters. Days-to-flowering, 100-seed mass, and seeds per pod were predominantly under the control of additive genetic variance, while both additive and non-additive genetic components of variance were important for days-to-maturity, plant height, primary and secondary branches, pods per plant, and seed yield. The F₁ and F₂ generations were found equally useful in estimating the genetic variances for different characters because the generation did not significantly interact with genetic parameters in the majority of cases. Sites or seasons, on the other hand, showed significant interaction with genetic components of variances; additive variance showed a larger interaction with environments than non-additive variance. This indicated the importance of more than one site and/ or season for unbiased estimation of the genetic components of variance. The results were compared with previous findings from diallel analyses.ICRISAT Journal Article No. 1200     

Identification of QTLs for seed and pod traits in soybean and analysis for additive effects and epistatic effects of QTLs among multiple environments

Soybean seed and pod traits are important yield components. Selection for high yield style in seed and pod along with agronomic traits is a goal of many soybean breeders. The intention of this study was to identify quantitative trait loci (QTL) underlying seed and pod traits in soybean among eleven environments in China. 147 recombinant inbred lines were advanced through single-seed-descent method. The population was derived from a cross between Charleston (an American high yield soybean cultivar) and DongNong594 (a Chinese high yield soybean cultivar). A total of 157 polymorphic simple sequence repeat markers were used to construct a genetic linkage map. The phenotypic data of seed and pod traits [number of one-seed pod, number of two-seed pod, number of three-seed pod, number of four-seed pod, number of (two plus three)-seed pod, number of (three plus four)-seed pod, seed weight per plant, number of pod per plant] were recorded in eleven environments. In the analysis of single environment, fourteen main effect QTLs were identified. In the conjoint analysis of multiple environments, twenty-four additive QTLs were identified, and additive QTLs by environments interactions (AE) were evaluated and analyzed at the same time among eleven environments; twenty-three pairs of epistatic QTLs were identified, and epistasis (additive by additive) by environments interactions (AAE) were also analyzed and evaluated among eleven environments. Comparing the results of identification between single environment mapping and multiple environments conjoint mapping, three main effect QTLs with positive additive values and another three main effect QTLs with negative additive values, had no interactions with all environments, supported that these QTLs could be used in molecular assistant breeding in the future. These different effect QTLs could supply a good foundation to the gene clone and molecular asisstant breeding of soybean seed and pod traits.     

鹰嘴豆种质资源农艺性状遗传多样性分析

以100份鹰嘴豆种质资源为材料,应用聚类分析和主成分分析方法,对15个主要农艺性状的遗传多样性进行分析。结果表明,参试材料存在广泛的遗传多样性。其中,多样性指数最高的是株高,其次是百粒重;性状变异系数最大的是单株荚数,其次是单株粒重;基于各种质间形态标记的遗传差异,将100份鹰嘴豆种质聚类并划分为4大类群。第Ⅰ类群可作为选育丰产中粒型和株高适中的品种,第Ⅱ类群可作为选育矮秆耐密及特异粒色(型)品种,第Ⅲ类群丰产性较差可作为选育子粒球型、光滑的品种,第Ⅳ类群可作为选育大粒型、适宜机械化收获的品种。9个数量性状的主成分分析结果表明,前4个主成分累计贡献率达73.91%,各主成分性状载荷值反映了主要数量性状的育种选择潜力。综合分析种质资源农艺性状,为鹰嘴豆的有效利用提供一定的科学依据。     

不同绿豆突变体主要农艺性状的多元遗传分析

对12个绿豆突变体的10个主要农艺性状进行了相关分析、主成份分析及聚类分析.分析结果表明：10个主要农艺性状的变异系数为16.01%（单株荚数）～3.64%（荚宽）.相关分析表明单株荚数与单株产量呈极显著的正相关;百粒重与单株产量呈显著的负相关;生育期与单株产量呈极显著的负相关.主成分分析结果表明前4个主成分（产量构成因子、单荚粒数因子、株型因子和荚宽因子）对变异的贡献率达87.45%;聚类分析后把12个绿豆突变体分为5类,各类之间单株产量差异明显.在绿豆突变体的选择中只有把不同性状综合考虑进去,才能够真正选择出性状优良的突变体.     

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.     

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     

大豆种质资源农艺性状和产量的年份间差异及其关系

明确大豆种质资源农艺性状的变化及其与产量的关系对大豆遗传育种具有重要的意义。以249份大豆种质资源为材料,应用多元统计方法分析了大田条件下两年间大豆农艺性状与产量的变化。结果表明,大豆种质资源的农艺性状和产量两年变异系数分别为6.2%~78.0%和6.3%~48.5%,变异较大。生育日数因在黄淮海区域生态类型较接近,变异系数较小;而主茎节数变异系数也较小。株高、有效分枝数、底荚高度、单株荚数、单株粒数、每荚粒数、单株粒重、百粒重、单位面积产量则相对变异较大。品种之间农艺性状和产量差异均显著。不同年份间生态因子（温度、降水量及日照时数）对大豆农艺性状和产量的影响较大,年份间不同指标差异亦显著。分别对两年农艺性状采用主成分分析,简化为4个与产量相关的独立指标,并建立了产量与农艺性状之间的方程Y=17.5-1.76x1+1.32x2+0.30x3+2.50x4和Y=198.8-3.12x1+7.71x2+0.08x3+2.71x4以表达其量化关系;采用聚类分析方法将两年中249份大豆种质资源分别聚为5类,并分析了各类品种的特性,为高产稳产大豆新品种的选育以及高产栽培措施的调控提供理论依据。     

Crop Growth, Disease and Yield Components of Rusted Phaseolus Beans in Ethiopia

Crop growth and disease epidemics in sprayed and non-sprayed bean plots, artificially infected with rust (Uromyces appendiculatus) 3 weeks after emergence. were assessed weekly in two cultivars, at two locations for two seasons. Disease intensity was regulated by the application of a fungicide at 5 spray frequencies. Fungicide application influenced leaf area index (LAI) and reduced rust intensity. The fungicide had no significant effect on other diseases and dead leaf area. Fungicide application increased seed yield (SY) by increased numbers of pods per plant (PP). Rust severity was strongly correlated with pustule density but the overall relationships among rust assessment parameters depended on cultivar and location. Seed yield and pods per plant were highly correlated with LAI. The relationships between LAI and seeds per pod or seed weight depended on cultivar and location. Overall rust assessment parameters (rust severity and pustule density) showed close, negative relationships with seed yield. seed weight and pods per plant but not with seeds per pod. The relationships obtained in the partially resistant line 6-R-395 were less definite than those in the susceptible line Mexican 142. The yield parameters seed yield and pods per plant, showed strong positive relationships.