Genetic diversity and population structure of groundnut (Arachis hypogaea L.) accessions using phenotypic traits and SSR markers: implications for rust resistance breeding

Abstract

Groundnut ( Arachis hypogaea L.) is a multi-purpose legume serving millions of farmers and their value chain actors globally. Use of old poor-performing cultivars contributes to low yields (< 1 t/ha) of groundnut in sub-Saharan Africa including Tanzania. The objectives of this study were to determine the extent of genetic variation among diverse groundnut collections using phenotypic traits and simple sequence repeat (SSR) markers to select distinct and complementary genotypes for breeding. One hundred and nineteen genotypes were evaluated under field conditions for agronomic traits and susceptibility to rust and leaf spot diseases. The study was conducted in two locations across two seasons. In addition, the 119 accessions were profiled with 13 selected SSR markers. Genotype and genotype by environment interaction effects were significant ( p < 0.05) for days to flowering (DTF), late leaf spot score at 85 and 100 days after planting, pod yield (PDY), kernel yield (KY), hundred seed weight (HSW) and shelling percentage (SP). Principal components analysis revealed that plant stand, KY, SP, NPP (number of pods per plant), late leaf spot and rust disease scores accounted for the largest proportion of the total variation (71.9%) among the tested genotypes. Genotypes ICGV-SM 08587 and ICGV-SM 16579 had the most stable yields across the test environments. Moderate genetic variation was recorded with mean polymorphic information content of 0.34 and gene diversity of 0.63 using the SSR markers. The majority (74%) of genotypes showed high membership coefficients to their respective sub-populations, while 26% were admixtures after structure analysis. Much of the variation (69%) was found within populations due to genotypic differences. The present study identified genotypes ICGV-SM 06737, ICGV-SM 16575, ICG 12725 and ICGV-SM 16608 to be used for development of mapping population, which will be useful for groundnut improvement. This study provided a baseline information on characterization and selection of a large sample of groundnut genotypes in Tanzania for effective breeding and systematic conservation. Electronic supplementary material The online version of this article (10.1007/s10722-020-01007-1) contains supplementary material, which is available to authorized users.

Assessment of the genetic diversity and population structure of groundnut germplasm collections using phenotypic traits and SNP markers: Implications for drought tolerance breeding

“…The population structure analysis showed three subpopulations, and most genotypes (68%) had a high membership coefficient to their respective subpopulations. This correlates with the findings reported by Daudi et al [ 67 ]. Genotypes with similar genetic backgrounds tended to cluster in the same sub-group, indicating the effectiveness of SNP markers used in this study in assigning the tested genotypes into homogenous groups [ 37 ].…”

Combining ability and gene action controlling rust resistance in groundnut (Arachis hypogaea L.)

“…The study used 12 parents selected from preliminary evaluation trials based on rust resistance, agronomic performance and SSR markers 28 . The lines consisted of accessions, a landrace and two released varieties (Table 2 ).…”

“…To initiate groundnut pre-breeding for rust resistance and farmer-preferred agronomic traits, genetically diverse collections were characterised using agronomic traits and polymorphic simple sequence repeat (SSR) markers. This enabled selection of potential and complementary parents for strategic breeding 28 . The combining ability effects of the selected parents and their progenies should be assessed to develop new breeding populations adapted to Tanzania.…”

Heterosis in Chickpea for Grain Productivity in Embu County, Kenya

“…Differences between crosses and their reciprocal for yield improvement have been reported (Yasar et al, 2014) in chickpeas. Other reports are in groundnuts, sorghum, pearl millet (Kamdar et al, 2020;Daudi et al, 2021;Shinda et al, 2021;Patil et al, 2021b). This indicates the existence of maternal influence in C. arietinum hybrids.…”