Pods Perplant Research Articles

Diversity of Major Yield Traits and Nutritional Components Among Greenhouse Grown Chickpea (Cicer arietinum L.) Breeding Lines, Landraces, and Cultivars of Different Origins.

This study analyzed the diversity of major yield traits and nutritional components across 122 chickpea breeding lines, cultivars, and landraces of different origins. All parameters showed significant variations, with a variance ranging from 4.61% in days to maturity (DM) to 43.04% in oleic acid. Six accessions, including CP021, CP022, CP026, CP037, CP066, and CP109, outperformed in yield traits and nutritional value. Origin significantly affected all phenotypic traits except total fatty acid contents, with Indian and Ukrainian accessions demonstrating contrasting performances. Most traits, except for the number of seeds per pod (SPP), palmitic acid, and total fatty acid contents, differed significantly among breeding lines, cultivars, and landraces. Breeding lines were the earliest to flower and to mature with average days to flowering (DF) of 50.23 days and DM of 101.50 days. They also had the highest average SPP, number of pods per plant (PPP), total seeds per plant (TSPP), total protein, crude fiber, dietary fiber, linoleic acid, and linolenic acid contents making them preferable for high yield and nutrition. Hierarchical cluster analysis classified the chickpea accessions into seven clusters, showing significant variations in yield traits and nutritional components. Principal component and Pearson's correlation analyses indicated positive correlations between DM and DF, and between SPP, PPP, and TSPP. Nutritional components also displayed varying associations, with a notable negative correlation between oleic and linoleic acids, the two essential fatty acids. Overall, this study showed the diversity of key phenotypic traits in chickpea breeding lines, cultivars, and landraces of different origins. The significant effects of genotype and origin differences on these traits could be used as a basis for future metabolomics and genomics research.

Genome-Wide Association for Morphological and Agronomic Traits in Phaseolus vulgaris L. Accessions.

Exploring genetic resources through genomic analyses has emerged as a powerful strategy to develop common bean (Phaseolus vulgaris L.) cultivars that are both productive and well-adapted to various environments. This study aimed to identify genomic regions linked to morpho-agronomic traits in Mesoamerican and Andean common bean accessions and to elucidate the proteins potentially involved in these traits. We evaluated 109 common bean accessions over three agricultural years, focusing on traits including the grain yield (YDSD), 100-seed weight (SW), number of seeds per pod (SDPD), number of pods per plant (PDPL), first pod insertion height (FPIH), plant height (PLHT), days to flowering (DF), and days to maturity (DPM). Using multilocus methods such as mrMLM, FASTmrMLM, FASTmrEMMA, ISIS EM-BLASSO, and pLARmEB, we identified 36 significant SNPs across all chromosomes (Pv01 to Pv11). Validating these SNPs and candidate genes in segregating populations is crucial for developing more productive common bean cultivars through marker-assisted selection.

Optimization of Genotyping‐by‐Sequencing (GBS) for Germplasm Fingerprinting and Trait Mapping in Faba Bean

ABSTRACTFaba bean (Vicia faba L.) is an important pulse crop with a wide range of agroecological adaptations. The development of genomic tools and a comprehensive catalog of extant genetic diversity are crucial for developing improved faba bean cultivars. The lack of a cost‐effective genotyping platform limits the characterization of large germplasm collections, understanding of genetic diversity across populations, and implementing breeder's tools like genomic selection. Genotyping‐by‐sequencing (GBS) offers high‐resolution genotyping for both model and crop plant species, even without a reference genome sequence. The genome fragments targeted by GBS depend substantially on the restriction enzyme (RE) used for the complexity reduction step. Species with complex genomic architecture require optimization of GBS with proper RE to realize the full potential of GBS. Here, we evaluated various REs in the GBS method and identified that the combination of ApeKI/MseI proved to be the most appropriate for faba bean based on the best library quality, a high number of genomic loci spread across chromosomes, and high enrichment loci associated with the gene space. With the new optimized protocol, we constructed a genetic map using a recombinant inbred line (RIL) population and identified a QTL for seed hilum color on Chromosome 1. In addition, we also genotyped a diversity panel and performed a genome‐wide association studies (GWAS) for important agronomic traits, including plant height (PH), flowering time (FT), and number of pods per plant (PPP). We identified six SNP markers significantly associated with these traits and listed potential candidate genes. The optimized faba bean‐specific GBS procedure will facilitate access to the untapped genetic diversity for genetic research and breeding and may facilitate functional genomics.

Genome-wide association study for yield-related traits in faba bean (Vicia faba L.).

Yield is the most complex trait to improve crop production, and identifying the genetic determinants for high yield is a major issue in breeding new varieties. In faba bean (Vicia faba L.), quantitative trait loci (QTLs) have previously been detected in studies of biparental mapping populations, but the genes controlling the main trait components remain largely unknown. In this study, we investigated for the first time the genetic control of six faba bean yield-related traits: shattering (SH), pods per plant (PP), seeds per pod (SP), seeds per plant (SPL), 100-seed weight (HSW), and plot yield (PY), using a genome-wide association study (GWAS) on a worldwide collection of 352 homozygous faba bean accessions with the aim of identifying markers associated with them. Phenotyping was carried out in field trials at three locations (Spain, United Kingdom, and Serbia) over 2 years. The faba bean panel was genotyped with the Affymetrix faba bean SNP-chip yielding 22,867 SNP markers. The GWAS analysis identified 112 marker-trait associations (MTAs) in 97 candidate genes, distributed over the six faba bean chromosomes. Eight MTAs were detected in at least two environments, and five were associated with multiple traits. The next step will be to validate these candidates in different genetic backgrounds to provide resources for marker-assisted breeding of faba bean yield.

Agronomic Performances and Seed Yield Components of Lentil (Lens culinaris Medikus) Germplasm in a Semi-Arid Environment

Lentil (Lens culinaris Medik.) is widely known among grain legumes for its high nutritional quality, playing an important role in enhancing Mediterranean farming systems as a sustainable crop. Field experiments comparing 121 lentil accessions (microsperma and macrosperma types from different countries) were conducted in a semi-arid environment of south Italy over two growing seasons (2016/2017 and 2017/2018). Their agronomic performance was determined, focusing on phenological, morphological, productive, and qualitative variability. Changes in rainfall and temperatures affected the agronomic traits, especially yield components. In both years, the average grain yield (GY) (2.31 and 2.22 t ha−1, respectively) was above the threshold of 2 t ha−1. Consistent yield exceeding the field average in both growing seasons revealed the superiority of accessions from Egypt, Cyprus, Algeria, Nepal, and Tunisia. Moreover, microsperma yielded more (+0.31 and +0.41 t ha−1 in the first and second year, respectively) than macrosperma accessions. Flowering (DASF—days after sowing to flowering) and thousand seed weight (TSW) appeared to be the most important traits related to grain yield. Flowering earliness seems to act as a mechanism for overcoming abiotic stresses. The analysis of yield components revealed a different productive determinism within the two subspecies. As also highlighted by the Principal Component Analysis, microsperma accessions presented on average a significantly higher number of pods per plant (PP) and seeds per pod (SP), despite the considerable variability among countries of origin. The results showed phenological and morphological variability among genotypes, which should be taken into account in view of future selection programs focused on obtaining lentil ideotypes suitable for the Mediterranean environment.

Unraveling the Genetic Basis of Key Agronomic Traits of Wrinkled Vining Pea (Pisum sativum L.) for Sustainable Production.

Estimating the allelic variation and exploring the genetic basis of quantitatively inherited complex traits are the two foremost breeding scenarios for sustainable crop production. The current study utilized 188 wrinkled vining pea genotypes comprising historical varieties and breeding lines to evaluate the existing genetic diversity and to detect molecular markers associated with traits relevant to vining pea production, such as wrinkled vining pea yield (YTM100), plant height (PH), earliness (ERL), adult plant resistance to downy mildew (DM), pod length (PDL), numbers of pods per plant (PDP), number of peas per pod (PPD), and percent of small wrinkled vining peas (PSP). Marker-trait associations (MTAs) were conducted using 6902 quality single nucleotide polymorphism (SNP) markers generated from the diversity arrays technology sequencing (DArTseq) and Genotyping-by-sequencing (GBS) sequencing methods. The best linear unbiased prediction (BLUP) values were estimated from the two-decades-long (1999–2020) unbalanced phenotypic data sets recorded from two private breeding programs, the Findus and the Birds eye, now owned by Nomad Foods. Analysis of variance revealed a highly significant variation between genotypes and genotype-by-environment interactions for the ten traits. The genetic diversity and population structure analyses estimated an intermediate level of genetic variation with two optimal sub-groups within the current panel. A total of 48 significant (P < 0.0001) MTAs were identified for eight different traits, including five for wrinkled vining pea yield on chr2LG1, chr4LG4, chr7LG7, and scaffolds (two), and six for adult plant resistance to downy mildew on chr1LG6, chr3LG5 (two), chr6LG2, and chr7LG7 (two). We reported several novel MTAs for different crucial traits with agronomic importance in wrinkled vining pea production for the first time, and these candidate markers could be easily validated and integrated into the active breeding programs for marker-assisted selection.

Zinc Oxide Nanoparticles Interplay With Physiological and Biochemical Attributes in Terminal Heat Stress Alleviation in Mungbean (Vigna radiata L.).

Gradually rising atmospheric temperature is the vital component of the environment, which is anticipated as the riskiest abiotic stress for crop growth. Nanotechnology revolutionizing the agricultural sectors, notably, zinc oxide nanoparticles (nano-ZnO) has captured intensive research interests due to their distinctive properties and numerous applications against abiotic stresses. Mungbean (Vigna radiata L.), being a summer crop, is grown all over the world at an optimum temperature of 28–30°C. A rise in temperature above this range, particularly during the flowering stage, can jeopardize the potential performance of the plant. Hence, an outdoor study was performed to evaluate the effect of multiple suspensions of nano-ZnO (0, 15, 30, 45, and 60 mg l–1) on physicochemical attributes and yield of mungbean crop under heat stress. Heat stress was induced by fine-tuning of sowing time as: S1 is the optimal sowing time having day/night temperatures <40/25°C and S2 and S3 are late sown that were above >40/25°C during the flowering stage. In vitro studies on Zn release from nano-ZnO by inductively coupled plasma mass spectroscopy (ICPMS) disclosed that the Zn release and particles uptake from nano-ZnO were concentration-dependent. Exogenous foliar application of nano-ZnO significantly upstreamed the production of antioxidants and osmolytes to attenuate the shocks of heat stress in S2 and S3. Likewise, nano-ZnO substantially rebated the production of reactive oxygen species in both S2 and S3 that was associated with curtailment in lipid peroxidation. Adding to that, foliar-applied nano-ZnO inflates not only the chlorophyll contents and gas exchange attributes, but also the seeds per pod (SPP) and pods per plant (PPP), which results in the better grain yield under heat stress. Thus, among all the sowing dates, S1 statistically performed better than S2 and S3, although foliar exposure of nano-ZnO boosted up mungbean performance under both the no heat and heat-induced environments. Hence, foliar application of nano-ZnO can be suggested as an efficient way to protect the crop from heat stress-mediated damages with the most negligible chances of nanoparticles delivery to environmental compartments that could be possible in case of soil application.

Phenotypic description of elite cowpea (Vigna ungiculata L. Walp) genotypes grown in drought-prone environments using agronomic traits

Identification and selection of cowpea genotypes possessing suitable agronomic attributes is key for cultivar development to increase production. The objective of this study was to evaluate cowpea genotypes using agronomic traits to aid selection and identification of best genotypes for adoption and breeding to develop high-yielding cultivars. Agronomic traits of 20 cowpea genotypes were evaluated under Tompi Seleka and Polokwane environments using a completely randomised block design. Significant (P ≤ 0.01) genotype effect was identified for agronomic traits, whereas environment effect was significant (P ≤ 0.05) for number of productive branches (NB), leaf width (LW), leaf length (LL), hundred-seed weight (HSW) and grain yield (GY). Significant genotype-by-environment interaction effect was observed for pod length (PL), pod width (PW) and number of seeds per pod (SPP). Correlation analysis revealed positive and significant associations between NB with LW (r = 0.58; P ≤ 0.01), LL (r = 0.67; P ≤ 0.01), number of pods per plant (PPP) (r = 0.56; P ≤ 0.01) and HSW (r = 0.47; P ≤ 0.05). LW was positively and significantly correlated with LL (r = 0.71; P ≤ 0.00), PPP (r = 0.56; P ≤ 0.01) and SPP (r = 0.58; P ≤ 0.01). Positive and significant correlation was observed between LL with chlorophyll content index (CCI) (r = 0.54; P ≤ 0.05), PPP (r = 0.68; P ≤ 0.01) and pod length (PL) (r = 0.52; P ≤ 0.05). PW was positively and significantly associated with PL (r = 0.68; P ≤ 0.01) and SPP (r = 0.61; P ≤ 0.01), whereas PL was positively associated with SPP (r = 0.82; P ≤ 0.01). Cowpea genotypes CH14, Embo buff, IT89D-349, IT96D-602, Veg cowpea 1, Veg cowpea 2, Veg cowpea 3 and Veg cowpea dakama red recorded high NB, plant height (PH), LL, LW, chlorophyll content index (CCI), number of pods per plant (PPP), HSW and GY. Also, genotypes 2460, IT96D-748, Oukawa, Ukaluleni, Veg cowpea dakama cream and Vigna Onb were associated with PL, SPP and PW. The identified genotypes possessing suitable agronomic traits are recommended for farmer-adoption and inclusion in breeding programs for cultivar development.

Application of machine learning and genetic optimization algorithms for modeling and optimizing soybean yield using its component traits.

Improving genetic yield potential in major food grade crops such as soybean (Glycine max L.) is the most sustainable way to address the growing global food demand and its security concerns. Yield is a complex trait and reliant on various related variables called yield components. In this study, the five most important yield component traits in soybean were measured using a panel of 250 genotypes grown in four environments. These traits were the number of nodes per plant (NP), number of non-reproductive nodes per plant (NRNP), number of reproductive nodes per plant (RNP), number of pods per plant (PP), and the ratio of number of pods to number of nodes per plant (P/N). These data were used for predicting the total soybean seed yield using the Multilayer Perceptron (MLP), Radial Basis Function (RBF), and Random Forest (RF), machine learning (ML) algorithms, individually and collectively through an ensemble method based on bagging strategy (E-B). The RBF algorithm with highest Coefficient of Determination (R2) value of 0.81 and the lowest Mean Absolute Errors (MAE) and Root Mean Square Error (RMSE) values of 148.61 kg.ha-1, and 185.31 kg.ha-1, respectively, was the most accurate algorithm and, therefore, selected as the metaClassifier for the E-B algorithm. Using the E-B algorithm, we were able to increase the prediction accuracy by improving the values of R2, MAE, and RMSE by 0.1, 0.24 kg.ha-1, and 0.96 kg.ha-1, respectively. Furthermore, for the first time in this study, we allied the E-B with the genetic algorithm (GA) to model the optimum values of yield components in an ideotype genotype in which the yield is maximized. The results revealed a better understanding of the relationships between soybean yield and its components, which can be used for selecting parental lines and designing promising crosses for developing cultivars with improved genetic yield potential.

Response of early maturity soybean cultivars to row spacing in full-season crop and double-crop systems

Cultivar selection and crop systems are important factors for maximising soybean seed yield. The effect of row spacing (RS1 = 75 cm, RS2 = 25 cm) on the performance of 10 early maturity soybean cultivars grown in full-season and double-crop system for two consecutive years was studied. The agronomic traits measured were seed yield (SY), plant height (PH), pods per plant (PP), first pod height (FPH), crude protein. RS had a significant effect on SY, PH, PP and FPH. Higher SY (P &amp;lt; 0.01) was recorded in RS2 regardless of the crop system. The double-crop system yield reduction index of the tested cultivars ranged from 30.0% to 56.4% and from 21.5% to 57.2% for RS1 and RS2, respectively. Cultivars differed (P &amp;lt; 0.01) for all traits in both RS and crop systems. Maturity Group I cultivars showed the highest productivity; the cultivars PR92B63 and Atlantic were better adapted to the full-season crop system (SY &amp;gt; 5.67 t/ha); cv. Sphera was the most productive in the double-crop system (4.66 t/ha); cv. PR92M22 showed good adaptability to both cropping systems. In conclusion, the significant effect of RS and crop system on SY was observed, whereas different high yielding cultivars were identified as suitable for full-season and double-crop system.

Effects of agro-climatic factors on yield components of grass pea (Lathyrus sativus L.)

Field experiment was conducted during rabi (winter) season of the year 2016–17 with grass pea (Variety: ‘Prateek’) sown on nine dates from 26th October to 21st December at weekly interval at Instructional Farm, Bidhan Chandra Krishi Viswavidyalaya, West Bengal to study the effect of agro-climatic factors on the yield components viz., number of pods per plant (PP), number of grains per pod (GP) and test weight of grains (TW). PP showed positive association with air temperatures during vegetative phase (Tmax: 0.70*; Tmin: 0.70* and Tmean: 0.70*). Significant positive correlations were observed between TW and average daily maximum temperature and diurnal temperature range during the postflowering phase (Tmax: 0.71* and Trange: 0.75*). Number of pods per plant could be predicted at the end of vegetative and reproductive stages with 69.9 and 70.1% predictability, respectively. On the other hand, test weight of grains could be predicted at the end of reproductive phase with 94.8% predictability.

Phenophasic development of wild Cicer species in relation to agroclimatic indices under rainfed and irrigated conditions

The field study was conducted on six wild chickpea accessions to evaluate the influence of agroclimatic indices viz., accumulated growing degree days (GDD), photo-thermal unit (PTU) and heliothermal unit (PTU) at various phenophases of chickpea under irrigated and rainfed conditions on yield of the plant. C pinnatifidum 212 witnessed highest accumulation of heat units at all stages of phenophasic development under irrigated and rainfed conditions. Agroclimatic indices depicted positive correlation with yield under rainfed conditions.Path coefficient analysis revealed that under irrigated conditions, yield attributes and agroclimatic indices showed strong positive correlation towards the final grain yield, though HTU at maturity indirectly affected yield via pods per plant (PPP) to the final yield in rainfed treatment. Among all the accessions, C pinnatifidum 212 performed better than other accessions by possessing high heat use efficiency (HUE) values, thus displaying their capacity of utilizing GDD and incorporating final yield.

Shade adaptive response and yield analysis of different soybean genotypes in relay intercropping systems

Soybean is one of the major oil seed crops, which is usually intercropped with other crops to increase soybean production area and yield. However, soybean is highly sensitive to shading. It is unclear if soybean morphology responds to shading (i.e., shade tolerance or avoidance) and which features may be suitable as screening materials in relay strip intercropping. Therefore, in this study, various agronomic characteristics of different soybean genotypes were analyzed under relay intercropping conditions. The soybean materials used in this study exhibited genetic diversity, and the coefficient of variations of the agronomic parameters ranged from 13.84 to 72.08% during the shade period and from 6.44 to 52.49% during the maturity period. The ratios of shading to full irradiance in stem mass fraction (SMF) were almost greater than 1, whereas opposite results were found in the leaves. Compared with full irradiance, the average stem length (SL), leaf area ratio (LAR) and specific leaf area (SLA) for the two years (2013 and 2014) increased by 0.78, 0.47 and 0.65 under shady conditions, respectively. However, the stem diameter (SD), total biomass (TB), leaf area (LA), number of nodes (NN) on the main stem, and number of branches (BN) all decreased. During the shady period, the SL and SMF exhibited a significant negative correlation with yield, and the SD exhibited a significant positive correlation with yield. The correlation between the soybean yield and agronomic parameters during the mature period, except for SL, the first pod height (FPH), 100-seed weight (100-SW), and reproductive growth period (RGP), were significant (P<0.01), especially for seed weight per branch (SWB), pods per plant (PP), BN, and vegetative growth period (VGP). These results provide an insight into screening the shade tolerance of soybean varieties and can be useful in targeted breeding programs of relay intercropped soybeans.

Seventy‐five Years of Improvement of Yield and Agronomic Traits of Soybean Cultivars Released in the Yellow‐Huai‐Hai River Valley

Yellow‐Huai‐Hai River Valley (YHH) in China has a long history of soybean [Glycine max (L.) Merr.] breeding. The genetic improvement of yield and agronomic traits of soybean cultivars due to breeding is rarely documented. The objectives were to analyze the trend of changes on widely‐grown soybean cultivars in this region. Twenty‐five soybean cultivars released over the period from 1929 until 2004 were selected. The field trial was conducted in three locations in 2 yr (2009–2010) and one location in 2011. Linear, bilinear, and quadratic regression models were built and compared to determine the rate of change for each trait. The yield gain was 9.97 kg ha–1 yr–1 during the eight decades. Current cultivars had shorter plant height, fewer nodes, higher lodging resistance, fewer pods per plant, fewer seeds per plant, more seeds per pod, higher 100‐seed weight (100‐SW) and higher yield than ancestral cultivars. The changing rates of these traits were either constant or variable with linear or quadratic models. Plant height (PH), height of the lowest pod (HLP), and seeds per pod (SPPOD) of new cultivars were more stable across environments than old cultivars, whereas lodging score (LS) and yield were less stable across environments. Yield increase was mainly attributed to an increase in SPPOD and seed weight rather than pods per plant (PPP). Collectively, improvements in agronomic and yield traits were significant during the 75‐yr‐long breeding effort. This study also shed light on developing future breeding strategies in the YHH.

Effect of irrigation regime on yield and yield components of soya bean

This study examines the effects of different irrigation regimes on seed yield and yield components of sprinkler-irrigated soya bean [(Glycine max (L.) Merr.] under field conditions in 2006, 2007 and 2008 in Zemun Polje (Srem, Srbija). Four irrigation regimes: 80-85% (T1), 70-75% (T2), 60-65% (T3) of field capacity, and non-irrigated regime (T0) were evaluated each experimental year. The experimental design was a randomised complete block with four replications on a Calcaric Chernozem. Water stress (drought) during growing season in the non-irrigated treatment (T0) decreased plant physiological activity, vegetative growth, and productivity of soya bean. Irrigation treatments significantly (P &lt; 0.01) influenced soya bean seed yield and yield components. The treatment T2 produced higher seed yield than T1 and T3. Irrigation regimes had statistically significant different effects on yield components such as the plant height at harvest, number of pods per plant, number of seeds per plant, mass of pod with seeds per plant, 1,000 seed mass and hectoliter mass of soya bean seeds. Yield reduction was mainly due to a lower number of pods and seeds per plant and lower seed mass. The T1 treatment had the highest plant height of soya bean in all three growing years. The results have shown that under water scarcity, the treatment T3 is an acceptable irrigation strategy to stabilize and increase soya bean yield in Srem and neighboring countries in the region, provided that this practice is not prevented by economic constraints.

Identifying water-responsive and drought-tolerant chickpea genotypes

This study quantifies the responses of drought-tolerant genotypes of chickpea (Cicer arietinum L.) to water availability under three irrigation regimes: rainfed (T1), 30% of full supplemental irrigation (T2), and full supplemental irrigation (T3). Sixteen genotypes of chickpea were tested in a split-plot arrangement in a randomised complete block design with three replications. Drought-resistance score (DRS), days to 50% flowering, plant height, days to maturity (DTM), grain yield (GY), biological yield (BY), 100-seed weight, average number of pods per plant (PoN), and average number of seeds per plant (SN) were measured. ANOVA indicated significant differences between treatments, years, and genotypes. Two genotypes, FLIP03-145C and ILC588, showed high drought tolerance accompanied by lower DTM, and they produced the highest GY (9.3 g plant–1). Strong and significant (P &lt; 0.001) correlations were observed between GY and BY (0.94), SN (0.93), and PoN (0.94). The GY, BY, SN, and PoN traits were significantly (P &lt; 0.001) correlated with DRS (–0.51 to –0.58). Ten genotypes performed better under T2 than T3, indicating a limitation in response to more water availability. Three genotypes (FLIP03-145C, ILC3182, and ILC588) are recommended for the national programs of Mediterranean countries as being drought-tolerant and especially responsive to water.

Effect of salinity stress on mungbean [Vigna radiata (L.) Wilczek] during consecutive summer and spring seasons

Mungbean is an ecologically important food grain legume crop. Susceptibility towards salinity stress has limited the productivity of mungbean. The effect of salt stress on two popular mungbean varieties ("Pusa vishal" and "Pusa ratna") has been compared during summer and spring seasons. The experiment was carried out at two salinity stress levels (50 mM and 75 mM NaCl). Significant variations and adaptability among stressed and non-stressed plants were observed in both varieties. The plants in early vegetative stage were found more resistant to salinity as compared to plants in late vegetative and reproductive stage. Salt stress, high temperature and salinity induced osmotic stress severely limited the plant growth, morphology, physiology and yield characteristics during summer. Measured parameters were less affected during spring season. The tolerant variety ?Pusa vishal? exhibited less reduction in plant height, total chlorophyll and carotenoid contents, plant length, leaf area, rate of photosynthesis, number of pods per plant and grain yield at high salinity level. However, the susceptible variety ?Pusa ratna? showed higher reduction for the measured parameters under salinity stress. A delay in pod ripening during spring season resulted in less pod-shattering. The present study may help to execute further research on screening of large mungbean germplasm for salt tolerance during spring season. The germplasm screening may help to identify resistant genotypes for genetic improvement of mungbean for growing in saline soil.

Resposta do feijão-caupi a estirpes fixadoras de nitrogênio em Gurupi-TO

Este estudo avaliou o efeito da inoculação com cepas fixadoras de nitrogênio na cv. Caupi de Vinagre em condições do sul do estado do Tocantins. O experimento foi realizado na safra 2007/2008. O delineamento experimental foi em blocos casualizados, com sete tratamentos e quatro repetições. Foram testados cinco inoculantes de bactérias: BR3301, BR3302, BR3262, BR3267 e BR3299, dois controles, um com NPK e um controle sem fertilização ou inoculação. Aos 35 e 55 dias após a emergência foram avaliadas as seguintes variáveis: número de nódulos, massa seca dos nódulos, massa seca dos brotos e eficiência relativa. No final do ciclo foi avaliado o número de vagens por planta, o peso das vagens por planta e o rendimento de grãos. Os dados foram submetidos à análise de variância pelo teste F e as médias foram agrupadas por Scott-Knott, ambas com 5% de probabilidade. A associação entre as médias foi avaliada pela correlação de Pearson. A cepa BR3302 apresentou maior peso seco dos nódulos aos 35 e 55 DAE, porém o controle sem fertilização ou inoculação e o NPK contribuíram para maior produtividade de grãos. O número de vagens e o peso das vagens por planta foram as variáveis ​​que mais influenciaram o rendimento. É necessário um estudo mais aprofundado sobre a seleção de linhagens de bactérias fixadoras de nitrogênio às condições ecológicas do estado do sul do Tocantins.

Relationship Among Yield Components and Selection Criteria for Yield Improvement in Early Rapeseed ( Brassica napus L.)

The objective of this study was to determine the relationship between seed yield and other important agronomic traits of early-maturing rapeseed as a rotation crop in a double-cropping rice area using Pearson's correlation coefficient as well as to estimate direct and indirect effects of specific yield component traits on seed yield via path analysis. Nineteen rapeseed genotypes were grown at ten environments in South China during 2008-2009 and 12 characters were evaluated. Analysis of variance showed that environment had a significant impact on all characters. For most characters the genotype by environment interaction was weak and not statistically significant. Simple correlation analysis indicated that the number of primary branches (PB), number of pods on the main raceme (PR), and number of seeds per pod made significant contributions to seed yield per plant (SYP), while 1 000-seed weight was negatively correlated with SYP ( r=−0.485, P<0.05). Furthermore, number of pods per plant (PP), PB, and PR had the greatest direct effects on SYP. In addition, PP and PB were the best indicators to predict seed yield in stepwise regression analysis. Finally, yield component differences between early- and medium-maturity varieties were compared; this showed that to improve the seed yield of early varieties, more emphasis should be given to increase PP, PB, and PR, and reduce plant height and shortening of growth duration in breeding practice.

Combining ability analysis and association of yield and yield components among selected cowpea lines

The study was carried out to determine combining ability and association of yield and yield components among crosses derived from seven selected cowpea (Vigna unguiculata (L.) Walp) parents. Twenty-one hybrids were generated from diallel crosses excluding reciprocals. Hybrids along with seven parents were studied for combining ability and phenotypic correlations for seed yield and eight yield components. The result indicated that the general combining ability (gca) and specific combining ability (sca) were significant for most characters indicating the importance of both additive and non-additive genetic components. Additive gene action was important for eight characters except pod number, whereas non-additive gene action was not important for nodule number and grain yield. Parental lines IT86D-716 and IT81D-985 were found to be good general combiners for grain yield and other traits. The most promising specific combiners for yield and yield components were from crosses including IT87D-697-2 × IT86D-716, IT88D-867-11 × IT86D-716, IT93K-624 × IT87D-697-2, and IT87D-697-2 × IT92KD-405-1. Significant positive phenotypic correlations were observed between seed yield with pod length (POL), number of pods per plant (PON), and number of seeds per pod (SPD). POL, pod number per plant, SPD, and grain yield were identified as the best selection criteria that could be used in cowpea breeding programs.