Variation in oil content and fatty acid composition of linseed (Linum usitatissimum L.) cultivars and their hybrids in sub-mountainous Himalayan region of India

The study assessed the level of variation in oil content and fatty acid composition of linseed cultivars, elite lines and hybrids in sub-mountainous Himalayan region of India. The oil content ranged from 34.60 to 41.14 % in the experimental material. Yellow seeded cultivars had higher oil content in comparison to brown seeded genotypes. Two saturated (Palmitic and steric acid) and three unsaturated fatty acids (Oleic, linoleic and linolenic acid) identified by gas chromatography represented 8.81% and 90.89% of the total oil, respectively. Widest range of variation was observed for linolenic acid followed by oleic acid,while the highest GCV was recorded for linoleic acid. Cross combinations exhibited wider range of variation for linolenic acid in comparison to the parents. All the traits exhibited low heritability and low genetic advance except 1000-seed weight. Oil content showed weak positive association with seed weight. Palmitic acid also showed positive association with oleic acid however, linoleic acid had negative association with linoleic, oleic and stearic acid. Results indicated that induced mutagenesis coupled with recombination breeding will be more beneficial for the development of low linolenic acid lines in linseed

Genomic prediction and quantitative trait locus discovery in a cassava training population constructed from multiple breeding stages

Assembly of a training population (TP) is an important component of effective genomic selection‐based breeding programs. In this study, we examined the power of diverse germplasm assembled from two cassava (Manihot esculenta Crantz) breeding programs in Tanzania at different breeding stages to predict traits and discover quantitative trait loci (QTL). This is the first genomic selection and genome‐wide association study (GWAS) on Tanzanian cassava data. We detected QTL associated with cassava mosaic disease (CMD) resistance on chromosomes 12 and 16; QTL conferring resistance to cassava brown streak disease (CBSD) on chromosomes 9 and 11; and QTL on chromosomes 2, 3, 8, and 10 associated with resistance to CBSD for root necrosis. We detected a QTL on chromosome 4 and two QTL on chromosome 12 conferring dual resistance to CMD and CBSD. The use of clones in the same stage to construct TPs provided higher trait prediction accuracy than TPs with a mixture of clones from multiple breeding stages. Moreover, clones in the early breeding stage provided more reliable trait prediction accuracy and are better candidates for constructing a TP. Although larger TP sizes have been associated with improved accuracy, in this study, adding clones from Kibaha to those from Ukiriguru and vice versa did not improve the prediction accuracy of either population. Including the Ugandan TP in either population did not improve trait prediction accuracy. This study applied genomic prediction to understand the implications of constructing TP from clones at different breeding stages pooled from different locations on trait accuracy