Globally, abiotic stresses, such as temperature (heat or cold), water (drought and flooding), and salinity, cause significant losses in crop production and have adverse effects on plant growth and development. A variety of DNA-based molecular markers, such as SSRs, RFLPs, AFLPs, SNPs, etc., have been used to screen germplasms for stress tolerance and the QTL mapping of stress-related genes. Such molecular-marker-assisted selection strategies can quicken the development of tolerant/resistant cultivars to withstand abiotic stresses. Oilseeds such as rapeseed, mustard, peanuts, soybeans, sunflower, safflower, sesame, flaxseed, and castor are the most important source of edible oil worldwide. Although oilseed crops are known for their capacity to withstand abiotic challenges, there is a significant difference between actual and potential yields due to the adaptation and tolerance to severe abiotic pressures. This review summarizes the applications of molecular markers to date to achieve abiotic stress tolerance in major oilseed crops. The molecular markers that have been reported for genetic diversity studies and the mapping and tagging of genes/QTLs for drought, heavy metal stress, salinity, flooding, cold and heat stress, and their application in the MAS are presented.

Ashwagandha is an important, medicinal, less exploited crop and most of its cultivated varieties are local cultivars. Information related to ashwagandha’s genetic diversity is very limited. Hybrid vigor exploitation may be useful in breaking its yield barrier at a commercial scale. A total of 45 F₁ crosses were produced during Kharif 2017-18 by using a line x tester matting design, which included three testers along with 15 lines. A total of 65 genotypes were grown in an RBD design, with three replications in three different environments during Kharif 2018-19, and observations were recorded for 11 different yield-attributing traits that were responsible for the estimation of the magnitude of the heterosis. An analysis of variance showed that a valuable amount of diversity existed in the breeding material. Based on the study, three promising crosses viz., UWS-305 × UWS-10, UWS-305 × RVA-100, and UWS-301 × RVA-100 were identified as superior heterotic materials for the root yield at harvest, whereas for the total alkaloid content, three excellent hybrids viz., UWS-309 × RVA-100, UWS-305 × RVA-100, and UWS-314 × RVA-100 were reported. Out of the above crosses, the cross-combination of UWS-305 × RVA-100 showed a significantly positive and useful heterosis on a pooled basis. Hence, the above crosses may be gainfully utilized in breeding programs for ashwagandha.

Ashwagandha [Withania somnifera (L.) Dunal] is an important medicinal plant which is major source of alkaloids, viz., withanine, sominiferine, sominiferinine, somnine, withananine and withasomnine. The genetic variability, correlation and path analysis of dry root yield and its contributing traits were analyzed in twenty seven diverse genotypes of Ashwagandha. The highest magnitude of genotypic and phenotypic coefficient of variation was recorded for number of primary branches per plant. The heightest heritability was coupled with high genetic gain was recorded for total alkaloid content, which indicated the importance of additive gene effect, which could be therefore improved through selection. The plant height positively correlated with dry root yield and root diameter but negatively correlated with days to 75% maturity. Among the characters, maximum direct effect was recorded for plant height followed by total alkaloid content. Superior genotypes, viz., MPAS-6, MPAS-4, MPAS-10, MPAS-5, and MPAS-1 could be gainfully utilized in the improvement of dry root yield in Ashwagandha.

The exotic and indigenous accessions were screened for utilization in breeding programmes. The higher estimates of variability parameters for grain yield, plant height, ear height, logging resistance and tassel branches indicated existence of genetic variation among the accessions. The higher heritability estimates along with higher genetic advance for plant height, ear height, grain yield and tassel branches, indicating presence of additive gene action (σ²A) for expression of such traits, which could be improved through direct selection. The correlation coefficient analysis expressed that grain yield could be improved with bold and larger seed size, since it was positively correlated with 100-kernal weight and ear aspect. The path coefficient analysis revealed that days to pollen shed and dry husk; number of upper leaveSi logging resistance; tassel branches and ear aspect exhibited positive direct effects, indicating that such traits contributed directly to grain yield. The exotic collection EC-411312 exhibited highest grain yield followed by EC-411353 and EC-452455 (46.11%, 42.01% and 38.52% superiority, respectively over best standard check) and can be used for development of improved cultivars.

Background: Maize production is subdued by many impediments that cause yield minimization. Among various biotic and abiotic stress factors, one significant cause of yield reduction in maize is drought stress. Methods: A set of 15 inbreds which were crossed with 3 narrow base testers in line × tester mating design, and resulting 45 F1s along with the parent inbreds and 3 commercial checks were then, in RCBD, subjected to drought stressed and well-watered conditions to assess their genetic worth during spring 2021. Result: The ANOVA unraveled significant mean sum of squares due to lines, testers and line × tester in pooled analysis for all the ten traits. The inbred EI-2188-2 followed by EI-2448 and EI-03-3 contained fair per se performance and significant high GCA effects over the environments for grain yield/plant, proline content and cob length whereas the cross EI-2448-1 × EI-2156 was found most promising hybrid with significant and high SCA effects across the environments regarding grain yield/plant, proline content and cob girth. Prevalence of non-additive type of genetic variance in governing most of the traits suggests adoption of heterosis breeding will be rewarding for improving yield and drought tolerance. Heterotic pooling of the highlighted inbreds and utilization of the superlative hybrids in further breeding programmes for drought tolerance is proposed.