Species diversity of genus Capsicum using agromorphological descriptors and simple sequence repeat markers

Sustainability of crops in most demand depends upon their genetic diversity. Capsicum, commonly called chilli, is one such crop with its fruits extensively used as vegetable across the world. Knowledge on various traits is important for genetic improvement of such species. Here, we assessed the genetic diversity among 10 genotypes of six Capsicum species, namely Capsicum annuum, C. chinense, C. chacoense, C. frutescens, C. tovarii and C. galapagoense. C. annuum MS-12 is a genetic male sterile line. We used morphological descriptors and simple-sequence repeat (SSR) molecular markers for this study. Out of 60 SSR screened, 22 markers (36.66%) showed polymorphism. Alleles number per locus varied from 3 to 7. Average PIC value for 22 polymorphic markers was 0.69, and ranged from 0.54 for the primer Hpms 1-139 to 0.85 for the primer CAMS-072. Ten genotypes of Capsicum species were grouped into three major clusters such that genotypes in a single cluster had less dissimilarity matrix values among themselves than which belongs to other clusters. Range of fruit weight and pericarp thickness varied from 0.1 g (‘PAU-621’) to 2.3 g (‘MS-12’), and from 0.29 mm (‘PAU-621’) to1.09 mm (‘MS- 12’), respectively. These two genotypes can be used in hybridization or in recombinant breeding program for obtaining higher heterotic effects/ heterosis or for transgressive segregants in chilli pepper

Species diversity of genus Capsicum using agromorphological descriptors and simple sequence repeat markers

906-915Sustainability of crops in most demand depends upon their genetic diversity. Capsicum, commonly called chilli, is one such crop with its fruits extensively used as vegetable across the world. Knowledge on various traits is important for genetic improvement of such species. Here, we assessed the genetic diversity among 10 genotypes of six Capsicum species, namely Capsicum annuum, C. chinense, C. chacoense, C. frutescens, C. tovarii and C. galapagoense. C. annuum MS-12 is a genetic male sterile line. We used morphological descriptors and simple-sequence repeat (SSR) molecular markers for this study. Out of 60 SSR screened, 22 markers (36.66%) showed polymorphism. Alleles number per locus varied from 3 to 7. Average PIC value for 22 polymorphic markers was 0.69, and ranged from 0.54 for the primer Hpms 1-139 to 0.85 for the primer CAMS-072. Ten genotypes of Capsicum species were grouped into three major clusters such that genotypes in a single cluster had less dissimilarity matrix values among themselves than which belongs to other clusters. Range of fruit weight and pericarp thickness varied from 0.1 g (‘PAU-621’) to 2.3 g (‘MS-12’), and from 0.29 mm (‘PAU-621’) to1.09 mm (‘MS12’), respectively. These two genotypes can be used in hybridization or in recombinant breeding program for obtaining higher heterotic effects/ heterosis or for transgressive segregants in chilli pepper

Variability studies for yield and its contributing traits in okra

Twelve okra genotypes were crossed in diallel fashion excluding reciprocals to generate 66 one-way hybrids. All the F1’s along with their parentswere grown at Vegetable Research Farm of the Department of Vegetable Crops, Punjab Agricultural University, Ludhiana, Punjab during therainy season of 2004-05. High genotypic and phenotypic coefficients of variation were noticed for number of primary branches per plantindicating maximum variability among the different genotypes. High estimates of heritability coupled with high genetic advance obtained fornumber of branches per plant, total yield per plant and marketable yield per plant indicating presence of additive gene effects which indicated theeffectiveness of selection for these traits. Presence of high heritability coupled with low genetic advance for days to fruit picking, average fruitweight, plant height, internodal length, number of fruits per plant, fruit diameter and average fruit length revealed that straight selection haslimited scope for further improving these traits

Phenotypic and genotypic characterization of tomato genotypes for resistance to root-knot nematode, Meloidogyne incognita

Root-knot nematode is a major constraint to tomato cultivation in open and protected structures. Resistance sources need to be continuously identified for combating pathogens affecting the yield. In the present studies, forty-seven genotypes of tomato were evaluated phenotypically along with their genotypic characterization. On the basis of their phenotypic reaction, the genotypes were grouped into four categories viz.: resistant, moderately resistant, susceptible and highly susceptible. Of these genotypes, only five were found to be resistant while forty-two were rated from moderately resistant to highly susceptible. Multiplication of Meloidogyne incognita was greatly reduced (Rf < 1) in resistant genotypes as compared to susceptible genotypes. Root galling index was also very low in resistant genotypes. Using molecular markers, the presence of the Mi-1.2 resistance gene was also confirmed in five resistant genotypes (L-0272, NR-14, L-097, L-0275 and PNR-7). These resistant sources could become a source of germplasm in breeding programs for the development of resistant cultivars.Le nématode à galles est une contrainte majeure à la culture de la tomate dans des structures ouvertes et protégées. Les sources de résistance doivent être identifiées en permanence pour lutter contre les agents pathogènes affectant le rendement. Jusqu’à présent, quarante-sept génotypes de tomate ont été évalués phénotypiquement, de même que leur caractérisation génotypique. Selon leur réaction phénotypique, les génotypes ont été regroupés en quatre catégories : résistant, modérément résistant, sensible et très sensible. Parmi ces génotypes, seuls cinq se sont révélés résistants tandis que quarante-deux ont été classés de modérément résistants à très sensibles. La multiplication de Meloidogyne incognita était fortement réduite (Rf < 1) dans les génotypes résistants par rapport aux génotypes sensibles. L'indice de galles racinaires était également très faible dans les génotypes résistants. À l'aide de marqueurs moléculaires, la présence du gène de résistance Mi-1.2 a également été confirmée dans cinq génotypes résistants (L-0272, NR-14, L-097, L-0275 et PNR-7). Ces sources résistantes pourraient devenir une source de matériel génétique dans les programmes de sélection pour le dévelop-pement de cultivars résistants

Advances in Omics Approaches for Abiotic Stress Tolerance in Tomato

Tomato, one of the most important crops worldwide, has a high demand in the fresh fruit market and processed food industries. Despite having considerably high productivity, continuous supply as per the market demand is hard to achieve, mostly because of periodic losses occurring due to biotic as well as abiotic stresses. Although tomato is a temperate crop, it is grown in almost all the climatic zones because of widespread demand, which makes it challenge to adapt in diverse conditions. Development of tomato cultivars with enhanced abiotic stress tolerance is one of the most sustainable approaches for its successful production. In this regard, efforts are being made to understand the stress tolerance mechanism, gene discovery, and interaction of genetic and environmental factors. Several omics approaches, tools, and resources have already been developed for tomato growing. Modern sequencing technologies have greatly accelerated genomics and transcriptomics studies in tomato. These advancements facilitate Quantitative trait loci (QTL) mapping, genome-wide association studies (GWAS), and genomic selection (GS). However, limited efforts have been made in other omics branches like proteomics, metabolomics, and ionomics. Extensive cataloging of omics resources made here has highlighted the need for integration of omics approaches for efficient utilization of resources and a better understanding of the molecular mechanism. The information provided here will be helpful to understand the plant responses and the genetic regulatory networks involved in abiotic stress tolerance and efficient utilization of omics resources for tomato crop improvement