RESUMO
Introduction: In the Asian tropics, unpredictable weather increases the risk of abiotic stresses in sorghum areas, making it harder to meet predicted demand. Genotype-by environment interaction (GEI) and the lack of an effective multi-trait-based selection approach make it challenging to breed climateresilient forage sorghum that adapts to nonconventional areas. Methods: The present investigation carried out to estimate genetic parameters, inter trait associations, genetic gain under selection (SGs) of 95 diverse forage sorghum genotypes. Fourteen forage yield and other secondary traits were evaluated at five different growing seasons at two locations. Negative and positive genetic gains under selection were estimated across different growing seasons including Kharif, Rabi and Summer in the year 2020 and 2021. Results and discussion: The GEI effects were significant (P < 0.001) for all the studied traits. The multi trait based stability indices have been said to assist breeders in ensuring sustained progress in primary traits likeforage yield without sacrificing genetic advancement in secondary traits. Fourteen genotypes were selected through each evaluation methods including genotype - ideotype distance index (MGIDI), multi-trait stability index (MTSI), multi-trait stability and mean performance (MTMPS) and multi-trait index based on factor analysis and genotype-ideotype distance (FAIBLUP Index), assuming 15% selection intensity. According to MGIDI, the selected genotypes exhibited desired positive genetic gains for dry forage yield per plant, inter-nodal length, green forage yield per plant, and plant height and negative genetic gains for days to 50% flowering. The strength and weakness plot is a potential graphical tool as portrayed by MGIDI, to identify and develop desirable genotype for particular environment. Two genotypes, G36 (302B) and G89 (348B) were found to be common across all four evaluation methods based on all the studied traits. Background: Multi-trait stability evaluation approaches are reliable and accessible for selecting multiple traits under varied testing environments with low multicollinearity issues. These tools proved effective in enhancing selection strategies and optimising breeding schemes for the development of climate-resilient forage sorghum genotypes. The aforementioned genotypes were found to be the most reliable, high-yielding, and earlymaturing and could be suggested for variety and hybrid development and ideotype breeding programmes to ensure the food and nutritional security.
RESUMO
The traditional rice genotypes of Assam are considered to have biological value due to the presence of several bioactive compounds like flavonoids, polyphenols, and anthocyanins, which have antioxidant, anti-cancer, anti-diabetic, and anti-aging properties. The pigmented genotypes are considered to have high iron (Fe) content. However, the effect of Fe and Zinc (Zn) accumulation on anthocyanin content is yet to be studied in pigmented rice of Assam. We studied the Fe, Zn, and anthocyanin content in grains of 204 traditional rice of Assam, which are traditionally preferred for their nutraceutical properties. We performed phenotypic and biochemical compositional analyses of 204 genotypes to identify those having high Fe, Zn, and anthocyanin. We also carried out the differential expression of a few selected Fe and Zn transporter genes along with the expression of anthocyanin biosynthesis genes. Interestingly, all pigmented rice genotypes contained a higher amount of phenolic compound than the non-pigmented form of rice. We found the highest (32.73 g) seed yield per plant for genotype Jengoni followed by Kajoli chokuwa and Khau Pakhi 1. We also listed 30 genotypes having high levels of Fe and Zn content. The genotype Jengoni accumulated the highest (186.9 µg g-1) Fe, while the highest Zn (119.9 µg g-1) content was measured in genotype Bora (Nagaon), The levels of Ferritin 2 gene expression were found to be significantly higher in Bora (Nagaon) (> 2-fold). For Zn accumulation, the genotype DRR Dhan-45, which was released as a high Zn content variety, showed significant up-regulation of the ZIP4 gene at booting (> 7-fold), post-anthesis (7.8-fold) and grain filling (> 5-fold) stages followed by Bora (Nagaon) (> 3-fold) at post-anthesis. Anthocyanidin synthase gene, Flavanone 3-dioxygenase 1-like (FDO1), and Chalcone-flavanone isomerase-like genes were up-regulated in highly pigmented genotype Bora (Nagaon) followed by Jengoni. Based on our data there was no significant correlation between iron and zinc content on the accumulation of anthocyanin. This challenges the present perception of the higher nutritive value in terms of the micronutrient content of the colored rice of Assam. This is the first report on the detailed characterization of traditional rice genotypes inclusive of phenotypic, biochemical, nutritional, and molecular attributes, which would be useful for designing the breeding program to improve Fe, Zn, or anthocyanin content in rice.
