Influence of nutrients and plant growth regulators on growth parameters and yield of Pigeonpea (Cajanus cajan (L.) Millsp.)

Pigeonpea is the second most important pulse crop after chickpea in India. The yield of pigeonpea is very low due to indeterminate growth habit and poor source-sink relationship. Plant growth regulators are known to influence the source-sink relationship and stimulate the translocation of photo-assimilates thereby helping in effective flower formation, fruit and seed development and ultimately enhance productivity of the crops. With this background, a field experiment was conducted with pigeonpea (CO Rg 7) under irrigated condition in Tamil Nadu Agricultural University, Coimbatore. An experiment was aimed at determining the effect of various nutrients and growth-promoting hormones on the growth parameters and yield of pigeonpea (Cajanus cajan (L.) Millsp.). The Factorial Randomised Block Design was used in the field trial and was replicated three times. At the vegetative stage, the treatments included foliar sprays of growth inhibitors such as M2-Mepiquat chloride (MC) @ 500 pp, M3-Chlormequat chloride (CC) @ 500 ppm and M1- Control. At flower initiation and 15 days later, various plant growth regulators, such as T2-SA (100 ppm), T3-BR (0.1 ppm), T4-Napthyl acetic acid (40 ppm), T5-Nutrients (ZnSO4 @ 0.5 percent + H3BO3 @ 0.3 percent, T6-Mono Ammonium Phosphate @ 2 percent, and T7-TNAU Pulse Wonder @ 1 percent), T8-Nutrient consortia I (1%) and T9-Nutrient consortia II (1%), were used. Among the treatments, the combination of Chlormequat chloride and nutrient consortia treatments (M3T8&M3T9) had better performances in growth parameters and yield of pigeonpea (CO Rg 7). Foliar application of M3T8-Chlormequat chloride and Nutrient consortia I (1%) resulted significantly (P<0.05) in the highest Total dry matter production (64.85; 82.96 g plant-1), Leaf area (1629; 1873 cm-2 plant-1), Leaf area index (1.358; 1.561), Specific leaf weight (7.29; 10.34 mg cm-2) and Seed yield (1133 kg ha-1) when compared to other treatments. The present study that the application of a combined formulation of hormones and nutrients present in the nutrient consortia at the flowering and pod formation stages influenced the growth parameters and resulted in higher seed yield

Genetic variability studies for yield and its component traits in RIL population of blackgram (Vigna mungo (L.) Hepper)

Blackgram or Urdbean, being a fourth important pulse crop in India has low genetic variability, low harvest index and nosignificant improvement in its productivity till date. An inter sub specific mapping population was developed by crossingVBN(Bg) 5 x Vigna mungo var. silvestris 22/10 by single seed decent method. The genetic variability parameters werestudied in a RIL (Recombinant Inbred Line) population consisting of 193 lines and their parents. The higher estimates ofPCV were observed for all the traits when compared with GCV. However, GCV was found to be high for the traits singleplant yield, number of clusters per plant and number of pods per plant. High heritability per cent was observed for days tomaturity, number of seeds per pod and hundred seed weight. High genetic advance as per cent of mean was observed forplant height, number of clusters per plant, number of pods per plant, single plant yield and hundred seed weight. Highheritability coupled with high genetic advance as per cent of mean was observed for hundred seed weight. Transgressivesegregants were observed for all the traits. These could be used further for yield testing apart from utilizing it as prebreeding material. The mapping population could be used for mapping of genes for important traits

Cross species amplification of Adzuki Bean derived microsatellite markers in Asian Vigna species

The Vigna is one of the important genus of grain legumes which forms the source of dietary protein and seven species of thisgenus, are domesticated as food crops in Asia. In recent years, molecular marker technology has greatly accelerated breedingprograms for the improvement of various crops. Among the different DNA markers, microsatellite or simple sequencerepeats (SSRs) are the markers of choice for various genetic studies due to their co-dominant nature, loci specificity and highreproducibility. To date, only few reports are available on isolation and development of microsatellite markers in some of theVigna species. Therefore, the available SSR markers from other Vigna species should be validated for their transferabilityand utility in those species in which they are unavailable. In the present study, a set of 40 microsatellite primers pairs derivedfrom adzuki bean (Vigna angularis) were used to assess the transferability and tested for their ability to amplifymicrosatellite loci in different species of Asian Vigna. The materials for this study included eleven different genotypesbelonging to seven species of Asian Vigna such as V. mungo var silvestris, V. mungo, V.umbellata, V. trilobata, V.aconitifolia, V. radiata var sublobata and V. radiata. All the 40 SSR primer pairs showed cross species amplification andproduced a total of 158 alleles in the genotypes studied. The percentage of amplification varied for each species whichranged from 37.5% (V.trilobata-2) to 100% (V. mungo var silvestris and V.mungo), while others showed more than 50%amplification. Apart from amplification, sufficient levels of polymorphism were also observed between cultivated blackgramand greengram and their progenitors V. mungo var silvestris and V. radiata var sublobata respectively. These findingssuggest that microsatellite markers from adzuki bean could be used in genomic studies of other Vigna species and thus aid intheir improvement

Characterization of Pigeonpea Genotypes Based on DUS Traits

The research entails morphological characterization of pigeonpea genotypes based on qualitative traits which aids in varietal description and ensure genetic purity. The study was conducted at the Department of Pulses, Tamil Nadu Agricultural University during kharif, 2019 and rabi, 2019-2020. The experiment was conducted in Randomized complete block design with two replications. The 68-short duration pigeonpea genotypes were characterized and grouped based on 17 qualitative traits. The morphological characterization revealed that, more variation was identified for traits viz., pattern of streaks on standard petal, plant height, seed colour, seed shape and seed size. Sixty - eight genotypes were subjected to cluster analysis and were grouped into four major clusters with an average similarity of 80%. The similarity coefficient ranged from 0.65 to 1.00. The cluster I consisted of 60 genotypes. Two sub-groups were formed from Cluster I. The sub-group I had 59 genotypes at 84 per cent similarity, whereas the sub-group II consisted of the genotype ICPL19050. Cluster II was made up of six genotypes. The cluster II was divided into two sub-groups at 84 per cent similarity. Clusters III and IV were solitary clusters, each with a single genotype. The characterization of genotypes with specific traits could be used to identify the genotypes, maintenance of genetic purity and to utilize in future breeding programmes

Genetic diversity as assessed by ISSR markers in Blackgram (Vigna mungo (L.) Hepper)

An investigation was carried out on a collection of 23 blackgram genotypes involving 16 releasedvarieties, six pre release cultures and one wild species Vigna mungo var. silvestris to study the genetic diversityusing twelve ISSR primers. The number of alleles produced by different ISSR primers ranged from eight to 17with an average of 11.5 per primer and the level of polymorphism was found to be 82.05 percent. Similaritymeasures and clustering analyses were made using ISSR data. The resulting dendrogram distributed the 23blackgram genotypes into five main clusters. The highest genetic similarity coefficient was measured betweengenotypes CBG 671 and CBG 632. The results of PCoA were comparable to that of grouping based on UPGMAand 23 genotypes were grouped into four groups. Genotype Vigna mungo var. silvestris was placed separatelyfrom rest of the genotypes in both the analyses. Grouping of varieties using ISSR markers did not show anyrelevance to their pedigree. All the pre release cultures in one group revealed that only a portion of geneticvariation has been exploited. The results revealed that, genetic diversity is low among the varieties releasedfrom the respective institute and hence genotypes were grouped according to the research institutes from whichthey released. It suggests that the research institutes have to enlarge the genetic base for variety development

Genetic Stability of TGMS Hybrids in Dry Direct Seeded Rice

Rice is a water-loving crop and traditionally sown in the nursery and then transplanted to the puddled and waterlogged main field. Owing to climate change, water scarcity and labour shortage problems, rice is now cultivated in the dry direct seeded method. Owing to potential of hybrid rice in increasing both rice production and productivity, many countries are focusing on exploiting the benefits of this technology. To break the yield plateau in rice cultivation, Thermosensitive Genetic Male Sterile (TGMS) hybrids were found to be very effective. In the present study, 41 TGMS hybrids and 9 checks were evaluated for their stability and adaptability by dry direct seeded method in four locations viz., E1 - Allahabad, E2 - Lucknow, E3 - Dhamtari and E4 - Raipur. The TGMS hybrid G44 was predicted as an ideal hybrid by the GGE stability model that possessed high grain yield and stable performance over environments. It was followed by hybrids viz., G10, G14, G34, G11, G20 and G47 that had a stable performance with high yield. Hence, these TGMS hybrids were identified as high and stable yielders across environments and suitable for dry direct seeded rice ecosystems. Among the environments, E1 (Allahabad) and E4 (Raipur) were considered favourable environments as they possessed the highest discriminating power. The hybrids identified in the study can be utilized for breaking the yield barriers in rice and can be recommended for dry direct seeding in marginal and rainfed areas