Germplasm Lines Research Articles

Registration of Arkot 1112, Arkot 1114, and Arkot 1115 cotton germplasm lines

AbstractArkot 1112 (Reg. no. GP‐1139, PI 702559), Arkot 1114 (Reg. no. GP‐1140, PI 702560), and Arkot 1115 (Reg. no. GP‐1141, PI 702561) are conventional cotton (Gossypium hirsutum L.) germplasm lines released by the Arkansas Agricultural Experiment Station in November, 2022. The three lines share Arkot 0306 (PI 671966) as a common parent. The second parents for Arkot 1112, Arkot 1114, and Arkot 1115 were ‘UA222’ (US patent no. 8,859,862), Arkot 0309 (PI 669969), and Arkot 0316 (PI 669970), respectively. The three lines were compared with ‘UA48’ and UA222 in replicated field tests at four Arkansas sites over 5 years. Over these tests, each of the three lines produced about 11 and 25% higher lint yields than UA48 and UA222, respectively. Lint yields of Arkot 1115 exceeded those of Arkot 1112 and Arkot 1114. Over 10 locations of the 2019 Regional Breeders Testing Network test, lint yields of Arkot 1112, Arkot 1114, and Arkot 1115 were equal to each other and ranked third, fourth, and fifth, respectively, out of 22 genotypes, indicating that the lines have wide adaptation. Leaf pubescence, stem pubescence, and bract trichome density of the lines were higher than UA48 and similar to UA222. All three lines displayed high resistance to bacterial blight. The lines were more resistant to tarnished plant bug than UA48 but were more susceptible to tarnished plant bug than UA222. Fiber quality of Arkot 1115 approached that of UA48 (excellent fiber quality), whereas Arkot 1112 and Arkot 1114 was similar to UA222 (good fiber quality).

Evaluation, multiplication and deposition of sunflower germplasm accessions in medium term storage

During the year 2018-2019 a total of 700 germplasm lines were multiplied and evaluated during kharif 2018. Allthe accessions were sown in augmented block design and compared with three checks. Promising accessions were identified with high seed yield and medium oil content. The range for oil content was between 24 and 37%. The germplasm accessions identified for high seed yield and medium oil content were GMU-125, GMU-169, GMU- 251, GMU-272, GMU-396, GMU-928, and GMU-1102. The five accessions identified with 37.0% of oil content included GMU-466, GMU-663, GMU-1091, GMU-1106 and GMU-1140. After complete drying of the seeds, the cleaned seeds from each accession were deposited in the medium term storage (MTS) of IIOR with proper labeling. Out of total harvested seeds approximately 50.0 g of the seeds was packed in airtight aluminium package suitable for medium term storage and remaining seeds were stored as working germplasm.

Analysis of plant expression profiles revealed that aphid attack triggered dynamic defense responses in sorghum plant.

Sorghum [Sorghum bicolor (L.) Moench] is one of the most important cereal crops grown worldwide but is often attacked by greenbug (aphid). In response to aphid attack, host plant initiates a large transcriptional reorganization, leading to activation of the host defense genes in aphid-attacked plants. In this study, our objective was to analyze defensive responses of sorghum against aphid and identify aphid resistance genes in sorghum. For the experiments, seedlings developed from an aphid resistant germplasm line (PI 550607) were divided into two groups, then, one group was infested with greenbug ((Schizaphis graminum Rondani) and the other group was used as control (un-infested). In addition, seedlings of sorghum cultivar Tx 7000, a susceptible genotype, prepared under the same conditions, were used as a genetic control. Those plant samples were used to develop transcriptional profiles using the microarray method, from which 26.1% of the 1,761 cDNA sequences spotted on the microarray showed altered expression between two treatments at 4days after infestation. Sequence annotation and molecular analysis revealed that many differentially expressed genes (DEGs) were related to direct host defense or signal transduction pathways, which regulate host defense. In addition to common responsive genes, unique transcripts were identified in response to greenbug infestation specifically. Later, a similar transcriptional profiling was conducted using the RNA-seq method, resulted in the identification of 2,856 DEGs in the resistant line with a comparison between infested and non-infested at 4days and 4,354 DEGs in the resistant genotype compared to the susceptible genotype at 4days. Based on the comparative analysis, the data of RNA-seq provided a support for the results from the microarray study as it was noticed that many of the DEGs are common in both platforms. Analysis of the two differential expression profiles indicate that aphid triggered dynamic defense responses in sorghum plants and sorghum plant defense against aphid is a complex process involving both general defense systems and specific resistance mechanisms. Finally, the results of the study provide new insights into the mechanisms underlying host plant defense against aphids and will help us design better strategies for effectively controlling aphid pest.

Role of Genetic Variability and Their Associated Character on Yield Attributing Traits in Castor (Ricinus communis L.) Germplasm Lines

Castor (Ricinus communis L.) is an industrially important non-edible oil seed crop with limited genetic variation. It is consequently important to diversify the genetic base to utilize the diversity. The primary objective of this study was to assess the extent and significance of variability among castor genotypes concerning yield and its associated traits. A study with two hundred germplasm lines along with four checks on genotypes on variability, correlation, and path coefficient was carried out for nine traits. The genotypic coefficient of variation (GCV) and phenotypic coefficient of variation (PCV) values indicated the presence of broad variation for all characters except for days to 50 percent flowering, days to maturity, number of nodes, and oil content. However, high heritability coupled with high genetic advance as percent mean was observed for plant height, days to 50 percent flowering, days to maturity, number of nodes, total length of the primary spike, number of effective spikes, seed weight, and total yield. The character's plant height, number of nodes, total length of the primary spike, number of effective spikes, seed weight, and oil content show a positive significant correlation with the total yield. The path coefficient analysis indicates that the utmost positive direct effect on total yield was exerted by a number of effective spikes per plant. Hence it was concluded that selection for traits total length of the primary spike, number of effective spikes, and 100 seed weight beneficial in yield improvement programs of castor.

Identification of Climate-Smart Bread Wheat Germplasm Lines with Enhanced Adaptation to Global Warming.

Bread wheat (Triticum aestivum L.) is widely grown in sub-tropical and tropical areas and, as such, it is exposed to heatstress especially during the grain filling period (GFP). Global warming has further affected its production and productivity in these heat-stressed environments. We examined the effects of heatstress on 18 morpho-physiological and yield-related traits in 96 bread wheat accessions. Heat stress decreased crop growth and GFP, and consequently reduced morphological and yield-related traits in the delayed sown crop. A low heat susceptibility index and high yield stability were used for selecting tolerant accessions. Under heatstress, the days to 50% anthesis, flag-leaf area, chlorophyll content, normalized difference vegetation index (NDVI), thousand grain weight (TGW), harvest index and grain yield were significantly reduced both in tolerant and susceptible accessions. The reduction was severe in susceptible accessions (48.2% grain yield reduction in IC277741). The plant height, peduncle length and spike length showeda significant reduction in susceptible accessions, but a non-significant reduction in the tolerant accessions under the heatstress. The physiological traits like the canopy temperature depression (CTD), plant waxiness and leaf rolling were increased in tolerant accessions under heatstress. Scanning electron microscopy of matured wheat grains revealed ultrastructural changes in endosperm and aleurone cells due to heat stress. The reduction in size and density of large starch granules is the major cause of the yield and TGW decrease in the heat-stress-susceptible accessions. The most stable and high-yielding accessions, namely, IC566223, IC128454, IC335792, EC576707, IC535176, IC529207, IC446713 and IC416019 were identified as the climate-smart germplasm lines. We selected germplasm lines possessing desirable traits as potential parents for the development of bi-parent and multi-parent mapping populations.

Variability of Sarocladium oryzae [(Sawada) Games & Hawksworth] and identification of novel donors for sheath rot resistance among temperate germplasm lines of rice

AbstractSheath rot is one of the most destructive emerging diseases of rice in Asia and a significant loss (20–85%) to rice production is caused by this disease under temperate agro-climatic conditions of Kashmir. Disease is more prevalent in higher belts of valley where Japonica rice cultivation is more common. Also, late-maturing varieties are more likely to be attacked by sheath rot disease of rice. Information regarding the occurrence and distribution of any pathogen and its variability in the field is very much essential to devise a suitable disease management programme against the particular pathogen. The isolates of Sarocladium oryzae tested in the present study exhibited considerable variation in cultural characteristics, morphology and pathogenicity. The resistant sources for sheath rot disease of rice were identified among the temperate germplasm of rice under a relatively high inoculum concentration and disease pressure of all the variable isolates of S. oryzae. Among 219 rice genotypes screened for resistance against S. oryzae under field conditions, 42 genotypes were further evaluated under controlled epiphytotic conditions against all the 18 isolates of S. oryzae. Four genotypes (SKUA-354, ORN-V4, GS-183, GS357) were finally selected with high resistance against sheath rot disease of rice which can be utilized as potential donors for the development of disease-resistant varieties of rice against sheath rot.

Metabolic-GWAS provides insights into genetic architecture of seed metabolome in buckwheat

BackgroundBuckwheat (Fagopyrum spp.), belonging to the Polygonaceae family, is an ancient pseudo-cereal with high nutritional and nutraceutical properties. Buckwheat proteins are gluten-free and show balanced amino acid and micronutrient profiles, with higher content of health-promoting bioactive flavonoids that make it a golden crop of the future. Plant metabolome is increasingly gaining importance as a crucial component to understand the connection between plant physiology and environment and as a potential link between the genome and phenome. However, the genetic architecture governing the metabolome and thus, the phenome is not well understood. Here, we aim to obtain a deeper insight into the genetic architecture of seed metabolome in buckwheat by integrating high throughput metabolomics and genotyping-by-sequencing applying an array of bioinformatics tools for data analysis.ResultsHigh throughput metabolomic analysis identified 24 metabolites in seed endosperm of 130 diverse buckwheat genotypes. The genotyping-by-sequencing (GBS) of these genotypes revealed 3,728,028 SNPs. The Genome Association and Prediction Integrated Tool (GAPIT) assisted in the identification of 27 SNPs/QTLs linked to 18 metabolites. Candidate genes were identified near 100 Kb of QTLs, providing insights into several metabolic and biosynthetic pathways.ConclusionsWe established the metabolome inventory of 130 germplasm lines of buckwheat, identified QTLs through marker trait association and positions of potential candidate genes. This will pave the way for future dissection of complex economic traits in buckwheat.

Capturing genetic variability in chickpea (Cicer arietinum L.) germplasm, released varieties, and advanced breeding lines under heat stress environment in North Indian climatic condition

Temperatures beyond optimal level are detrimental to growth and production in chickpeas. Aiming at capturing genetic variabilityand identifying potential heat-tolerant chickpea genotype, a panel of 110 chickpea lines were evaluated in field under normal sown(non-stress) and late sown (heat-stress) environments for various phenological, yield and yield-related traits over two consecutive yearsunder field conditions. Significant genetic variability for the phenological and yield related) was recorded under both non-stress andheat-stress conditions for both years. Seed yield/plant had strong positive correlations with number of pods/plant and harvest indexunder heat stress, indicating selection of plants with high pods/plant and seed yield/plant could help develop a heat-tolerant chickpealine. Based on the yield and yield-related traits, JG74, JAKI9218, Pusa 547, GNG1958, RVG202, RSG11, RSG931, RSG10, GG2, and Pusa240genotypes were classified as promising lines under heat stress environment. The identified diverse heat-tolerant genotypes may beused as a potential source in chickpea breeding programme for enhancing heat tolerance and useful genetic variability.

Registration of eight germplasm lines of upland cotton (Gossypium hirsutum L.) resistant to reniform nematodes (Rotylenchulus reniformis) with elite agronomic performance

AbstractCotton (Gossypium hirsutum L.) germplasm lines BARBREN‐713‐8 (Reg. no. GP‐1138, PI 701080), BARBREN‐713‐11 (Reg. no. GP‐1131, PI 701073), BARBREN‐713‐13 (Reg. no. GP‐1132, PI 701074), BARBREN‐713‐25 (Reg. no. GP‐1133, PI 701075), BARBREN‐713‐32 (Reg. no. GP‐1134, PI 701076), BARBREN‐713‐33 (Reg. no. GP‐1135, PI 701077), BARBREN‐713‐41 (Reg. no. GP‐1136, PI 701078), and BARBREN‐713‐48 (Reg. no. GP‐1137, PI 701079) were developed and released by the USDA‐ARS, Texas A&M AgriLife Research, and Cotton Incorporated in 2014. The objective of the release was to provide breeders with agronomically elite germplasm that is resistant to reniform nematode (Rotylenchulus reniformis). Four lines (BARBREN‐713‐8, ‐32, ‐33, and ‐48) also have simple sequence repeat (SSR) DNA markers for the Mi‐1 or Mi‐2 gene for resistance to root‐knot nematode [Meloidogyne incognita (Kolfoid & White) Chitwood]. The lines have excellent seedling vigor in fields infested with both nematodes and fungal root‐rot pathogens. Resistance to reniform nematode was transferred from G. barbadense GB713 (PI 608139) and is associated primarily with the Ren2GB713 gene on chromosome 21. This gene could be detected with the codominant SSR marker BNL3279_105 or the single nucleotide polymorphism marker GI‐187401. In controlled environment assays, these lines reported here suppressed numbers of reniform nematode eggs by 74–92% compared with ‘FiberMax FM966’. The lines outyielded and had fiber quality equal to or greater than several commercial cultivars.

Genetic Diversity Studies and Fusarium Wilt Screening in Chickpea (Cicer arietinum L.) Germplasm

Background: The genetic base of chickpea has narrowed substantially during the domestication process (Thudi et al., 2016). Therefore, increasing the genetic divergence of chickpea has been a major goal for breeders. The assessment of genetic diversity of chickpea germplasm can provide a valuable information to the breeder for parental selection strategies in plant breeding programs. Method: Two hundred and eighty chickpea germplasm including two checks (JG-11 and SA-1) were tested with an objective to explore the genetic divergence by using Mahalanobis D2 statistics. The field experiment was carried out during Rabi 2021-22 at Zonal Agricultural Research Station (ZARS), Kalaburagi. The magnitude of genetic divergence was studied using data obtained from five quantitative traits. Results: The 280 genotypes including checks were divided into seventeen clusters based on their D2 values. Out of seventeen clusters, cluster II (89 genotypes) was the largest followed by cluster I (83 genotypes), cluster III (31 genotypes), cluster VIII (29 genotypes), cluster VII (24 genotypes), cluster VII (15 genotypes). Same set of germplasm were also screened for fusarium wilt in wilt sick plot, 30 germplasm lines showed resistant (10.71%), 83 moderately resistant (29.64%), 44 moderately susceptible (15.71%), 31 susceptible (11.07%) and 92 highly susceptible reaction to fusarium wilt. Clusters XIV and XVI had extreme genetic distance and the germplasm lines in these cluster also showed moderate resistance to fusarium wilt.

Evaluation of Germplasm Lines of Maize for Resistance to Fall Armyworm1 and Southwestern Corn Borer2 Leaf-Feeding Damage

Evaluation of Germplasm Lines of Maize for Resistance to Fall Armyworm1 and Southwestern Corn Borer2 Leaf-Feeding Damage

Correlation, Path Analysis and Genetic Divergence of Various Agro-morphological Traits and Traits Suitable for Mechanical Harvesting of Chickpea (Cicer arietinum L.) Germplasm

Five hundred and forty germplasm lines of chickpea were evaluated along with five checks (RLBGK-1, BG 3062, RVG 204, Phule Vikram, NBeG 47) in augmented design during rabi, 2021–2022 at Rani Lakshmi Bai Central Agricultural University, Jhansi, Uttar Pradesh, India to study the agro-morphological features and traits appropriate for mechanical harvesting. Correlation, path coefficient analysis and genetic divergence were estimated to find out the extent of association and genetic divergence among chickpea germplasm. Plant height, growth habit, the height of the initial podding node, and the angle of the primary branch are characteristics that have been researched to identify lines that are suited for mechanical harvesting. Peduncle length, number of primary branches, number of secondary branches, number of pods per plant, chlorophyll content, leaf area index, chlorophyll fluorescence showed positive correlation with seed yield per plant. Plant height and height of first podding node were showing positive high indirect effects through number of secondary branches on seed yield per plant. Cluster 1 was the largest with 399 germplasm while two clusters number 24 and 37 were smallest with 1 genotype each. Plant height and height of first podding node were exhibiting maximum mean in cluster 32, whereas seed yield per plant was having maximum mean in cluster 14. According to percent contribution of different characters to total divergence obtained, the most significant contributors to the divergence were number of pods per plant and plant height. Correlation analysis indicated that traits suitable for mechanical harvesting are not directly correlated with seed yield, while path coefficient analysis indicated that they have indirect effects on seed yield through number of primary and secondary branches per plant.

Registration of soybean germplasm line R14‐1422 with high yield and moderate resistance to southern root knot nematode

AbstractR14‐1422 (Reg. no. GP‐523, PI 702562) is a mid‐maturity group (MG) V (relative maturity 5.4), determinate growth habit, high‐yielding, conventional soybean [Glycine max (L.) Merr.] germplasm line developed and released in 2021 by the Arkansas Agricultural Experiment Station. R14‐1422 is an F4 selection from the cross between ‘R06‐4433’, a cultivar released by Arkansas, and the Missouri cultivar ‘S05‐11482’. Trial results of over 74 environments in Arkansas and other southern states showed that R14‐1422 is well adapted and provides high‐yielding performance. R14‐1422 is a MG V (5.4), line with determinate growth habit, white flowers, gray pubescence, and a tan pod wall at maturity. Seed of R14‐1422 has yellow cotyledon, yellow seed coat, and buff hilum color. R14‐1422 has high yield potential and moderate resistance to southern root‐knot nematode and is a chloride excluder.

Phenomics based prediction of plant biomass and leaf area in wheat using machine learning approaches.

Phenomics has emerged as important tool to bridge the genotype-phenotype gap. To dissect complex traits such as highly dynamic plant growth, and quantification of its component traits over a different growth phase of plant will immensely help dissect genetic basis of biomass production. Based on RGB images, models have been developed to predict biomass recently. However, it is very challenging to find a model performing stable across experiments. In this study, we recorded RGB and NIR images of wheat germplasm and Recombinant Inbred Lines (RILs) of Raj3765xHD2329, and examined the use of multimodal images from RGB, NIR sensors and machine learning models to predict biomass and leaf area non-invasively. The image-based traits (i-Traits) containing geometric features, RGB based indices, RGB colour classes and NIR features were categorized into architectural traits and physiological traits. Total 77 i-Traits were selected for prediction of biomass and leaf area consisting of 35 architectural and 42 physiological traits. We have shown that different biomass related traits such as fresh weight, dry weight and shoot area can be predicted accurately from RGB and NIR images using 16 machine learning models. We applied the models on two consecutive years of experiments and found that measurement accuracies were similar suggesting the generalized nature of models. Results showed that all biomass-related traits could be estimated with about 90% accuracy but the performance of model BLASSO was relatively stable and high in all the traits and experiments. The R2 of BLASSO for fresh weight prediction was 0.96 (both year experiments), for dry weight prediction was 0.90 (Experiment 1) and 0.93 (Experiment 2) and for shoot area prediction 0.96 (Experiment 1) and 0.93 (Experiment 2). Also, the RMSRE of BLASSO for fresh weight prediction was 0.53 (Experiment 1) and 0.24 (Experiment 2), for dry weight prediction was 0.85 (Experiment 1) and 0.25 (Experiment 2) and for shoot area prediction 0.59 (Experiment 1) and 0.53 (Experiment 2). Based on the quantification power analysis of i-Traits, the determinants of biomass accumulation were found which contains both architectural and physiological traits. The best predictor i-Trait for fresh weight and dry weight prediction was Area_SV and for shoot area prediction was projected shoot area. These results will be helpful for identification and genetic basis dissection of major determinants of biomass accumulation and also non-invasive high throughput estimation of plant growth during different phenological stages can identify hitherto uncovered genes for biomass production and its deployment in crop improvement for breaking the yield plateau.

Multivariate analysis of germplasm lines of pearl millet [Pennisetum glaucum (L.) R. Br.] for identification of dual-purpose cultivar

An experiment was conducted in a randomized complete block design with three replications to study the genetic variability in germplasm lines of pearl millet. A total of eight traits were taken including grain yield and dry fodder yield. Analysis of variance showed significant variability for all the studied traits. The grain yield ranged from 42.76 to 10.45 q/ha with an average mean of 20.32 q/ha, and the dry fodder yield ranged from 103.66 to 40.30 q/ha. There was little difference between PCV and GCV in the studied traits suggesting a minimum influence of environment. High estimates of heritability coupled with high/ moderate genetic advance were recorded for all traits indicating the presence of additive genetic variances. Correlation, regression and path analysis study revealed that grain yield was positively related to dry fodder yield, panicle length, panicle diameter and plant height. The first five principal components captured almost 90% of the variability, and the hierarchical clustering separated 28 germplasm lines into four groups. The studied germplasm lines have sufficient variability for grain and fodder yield. Selection of these germplasm lines in future breeding programmes would be rewarding to release dual-purpose cultivars.

Assessment of variability of Horse gram (Macrotyloma uniflorum (Lam.) Verdc) germplasmlines for morphological and physiological traits

The study was conducted to assess the mean, range and variance of various morphological and physiologicaltraits.The total of 108 horse gram germplasm lines along with checks (GPM-6,CRIDA-18R,CRHG-4) were grown inaugmented block design during kharif 2021-22 at the College of Agriculture,Vijayapur. Analysis of variance revealed that themean sum of squares attributable to germplasm lines vs checks were significant for all the traits except seed yield per plant,fodder yield per plant, test weight and SPAD chlorophyll meter reading at 30 and 60 days.The mean and range of horsegramgerm plasm lines for different characters like days to 50 percent flowering was 78.34 days and 58.00-87.48 days, respectivelyand for other traits like days to maturity was (147.83 days and119.14 days to171.81days), plant height (29.36cm and10.28to 42.70 cm), number of pods per plant (28.58 and 17.02 to 41.02), number of seeds per pod (4.52 and 3.29 to 6.02), testweight (3.69 g and 2.26 - 4.61g), fodder yield per plant (8.24 g and 4.02 to10.98 g), seed yield per plant (4.38g and 2.33g(CG-Kulthi) to 7.67g (GPM-19) and some of physiological traits like specific leaf weight (3.41mg/cm2and1.18-5.90mg/cm2),leaf area index which ranged from 1.13 to 5.54 with mean of 2.96. The range of genotypic variance and phenotypicvariance for seed yield and yield attributing traits was 0.04 to 56372.89,0.08 to 67584.39, while the magnitude of genotypicvariance and phenotypic variance was maximum for seed yield (56372.89 and 67584.39, respectively) and the range ofgenotypic variance and phenotypic variance for physiological traits was 0.28 to 64.80, 0.44 to100.30,the maximumgenotypic variance and phenotypic variance was recorded in seed yield (64.80 and 100.30, respectively).

Screening of Mustard Germplasm against Powdery Mildew (Erysiphe cruciferarum) and Analysis of Yield Contributing Characters

The current experiment was carried out at the Regional Agricultural Research Station (RARS) Polasa, Jagtial during rabi 2020-21, with the goals of (1) assessing the resistance of Indian mustard germplasm lines to powdery mildew disease and (2) analysing the yield and its contributing traits, days to 50% flowering, days to maturity, plant height in centimetres, primary branch number, secondary branch number, siliqua number and siliqua length in centimetres. The results of the analysis of variance showed that there were statistically significant differences between the genotypes and their characteristics. The genotypes viz., DRMR-150-35, Black gold, and RH-9304 performed best on average out of 50 different varieties for twelve different characteristics, including high seed yield per plant, high 1000-seed weight and high harvest index.Two resistant genotypes (GM-3 and Swarna Jyothi) and nine genotypes (Pusa mahak, PM-25, PM-26, PDZM-31, Pusa tarak, Pusa bahar, Ashirwad, DRMR-601, and JM-2) demonstrated considerable resistance reaction to the powdery mildew disease after being screened against the illness. We can solve the disease effect problem by utilizing these germplasm lines as donors in future breeding programme to develop powdery mildew resistant lines.

Studies on Genetic Diversity and Principal Component Analysis in Wheat Germplasm (Triticum aestivum L.)

This study aimed to assess the potential genetic diversity among wheat genotypes by using cluster analysis and principal component analysis for selection of desired parents in hybridization programmes. The study was carried out at the Crop Research Center, Department of Agriculture, Himgiri Zee University, Dehradun, Uttarakhand, during Rabi season 2021-2022 under irrigated conditions. Twenty germplasm lines of wheat (Triticum aestivum L.) were grown in Randomized Block Design with three replications with an objective to study the genetic variability and diversity through D2 statistics in wheat. The Analysis of variance revealed the significant differences among the genotypes for all the traits studied indicating that the presence of genetic material under the study. The clustering pattern as per Tocher’s optimization method obtained on the basis of magnitude of D2 value revealed that the twenty genotypes were grouped into five clusters. The maximum intra cluster D2 value was observed in cluster I (130.89) followed by cluster II (108.06) and cluster III (97.93). The inter cluster distance values ranged from 249.44 to 1101.59. The maximum inter cluster distance was observed between cluster II and IV (1101.59) followed by II and III (1017.07) that indicated wide divergence existed among the genotypes of these clusters. From the results obtained by Principal component analysis six principal components PC 1 to PC6, which are extracted from the original data and having latent roots greater than one thereby accounting to 84.30% of the total variation.

Assessment of Genetic Correlation, Path Coefficient Analysis and Principal Component Analysis in Horse Gram under Water Stress

A field experiment was conducted to evaluate the correlation and path analysis in thirty horse gram germplasm lines under moisture-stressed conditions using various selected characters. The association studies revealed a significant positive correlation of seed yield with relative water content, number of pods per plant, number of seeds per pod, total chlorophyll content, harvest index, proline content, root dry weight, root length and leaf area index. While days to 50% flowering, days to maturity, plant height and number of primary branches showed a significant negative correlation with yield. Path coefficient analysis revealed a high positive direct effect of the number of pods per plant on seed yield and the number of seeds per pod recorded exhibited the highest indirect effect on seed yield via the number of pods per plant under moisture stress conditions in horse gram. So, selection based on the number of pods per plant will be more beneficial under water stress conditions. The exploitation of genetic diversity is key to a successful breeding program. The principal component analysis using selected fifteen characters revealed the existence of adequate genetic variability among genotypes under study. First four principal components accounted for a cumulative variance of 82.47%. The principal component analysis (PCA) biplot revealed genotypes viz. IC22785, IC392329, HG 26L and IC20753 to highly diverse and these genotypes may be employed for enhancement of various traits in horse gram.

Evaluation of exotic soybean accessions and their use in developing improved soybean lines with resistance to Phomopsis seed decay.

Poor seed quality of soybean is often associated with Phomopsis seed decay (PSD), which is one of the most economically important seed diseases. Diaporthe longicolla (syn. Phomopsis longicolla) is the primary cause of PSD. Control of PSD is best accomplished by planting PSD-resistant cultivars. Sixteen exotic soybean accessions from the USDA soybean germplasm collection were screened for reaction to PSD at Stoneville, Mississippi. They consisted of maturity groups (MG) II, III and IV. Seeds from inoculated and non-inoculated plots harvested either promptly at maturity, or after a two-week delay in harvest, were assessed for infection by D. longicolla. Seed infection ranged from 0 to 36.7%. Overall, PI 417050 (MG II), PI 417017 (MG III), and PI 594692 (MG IV) had significantly (P ≤ 0.05) lower percentages of seed infected by D. longicolla and higher seed germinations than other genotypes in the same maturity groups. PI 587982A also performed well. As a result of these findings, these resistant accessions were used over multiple cycles of breeding to develop improved breeding lines with resistance to PSD and low seed damage. Breeding line 11043-225-72, with combined resistance from both PIs 417050 and 587982A, had low scores for PSD (6.7%) and seed damage (3.4%), while DS65-1, deriving resistance from PI 587982A, had the lowest seed damage score (1.1%) and the highest seed germination (85.6%) among all lines tested in 2017. DS65-1 and 11043-225-72, along with five other improved breeding lines, were provided to public soybean breeders for developing improved cultivars and germplasm lines. DS31-243 (PI 700941), derived from PI 587982A, was publicly released by the USDA in 2022. This research will lead to future releases of improved germplasm lines and cultivars with PSD resistance and high seed quality. It will also aid in disease management and be a benefit to soybean producers and the industry at large.