Genetic interrelationship among tepary bean (Phaseolus acutifolius A. Gray) genotypes revealed through SSR markers

Abstract

Tepary bean (Phaseolus acutifolius A. Gray) is one of the useful plant genetic resources possessing novel genes for abiotic and biotic stress tolerance. It is largely used in the breeding of common bean or related tropical legumes. The objective of this study was to determine the genetic interrelationship present among 20 diverse tepary bean genotypes using 10 selected and polymorphic simple sequence repeat (SSR) markers and to identify genetically unique parental lines for developing breeding populations. The SSR markers amplified a total of 57 putative alleles with a size range of 102 to 304 base pairs. Number of alleles ranged from 2 to 16 with a mean of 5.7 per locus. Number of effective alleles ranged from 1.5 to 11.6 with a mean of 4.32. The mean observed and expected heterozygosity were 0.45 and 0.51, respectively, reflecting moderate level of genetic interrelationship among the tested genotypes. The mean polymorphic information content (PIC) of the SSR loci was 0.50 suggesting that the selected markers had high discriminatory power for genetic diversity analysis of tepary bean. Genetic distances varied from 0.18 to 0.64 with a mean value of 0.42, signifying relatively low levels of genetic diversity among the studied genotypes. Cluster analysis grouped the genotypes into three distinct genetic groups. Unique genotypes such as G40201, G40237, G40158, G40157 and G40158 from Cluster I, G40084 and G40033 from Cluster III were selected. These are distantly related parents and recommended for further breeding or genetic recombination to broaden the genetic basis of tepary bean or related legumes.

Breeding tepary bean (Phaseolus acutifolius) for drought adaptation: A review

“…Also, tepary bean can be readily crossed with its wild relatives (Blair et al, 2003), which is useful to create genetic variation for development and advancement of families possessing key agronomic and physiological traits that improve yield gains under constrained environments. Though limited genetic divergence is reported among domesticated tepary bean genetic pool, genotypic differences exist for agronomic (Bhardwaj, Rangappa, & Hamama, 2002; Federici, Ehdaie, & Waines, 1990; Mhlaba, Amelework, Shimelis, Modi, & Mashilo, 2018a; Mohamed, Mohamed, Schmitz‐Eiberger, Keutgen, & Noga, 2005), physiological and biochemical (Mohamed et al, 2005; Türkan, Bor, Özdemir, & Koca, 2005) traits. This variation for key traits is useful and provides opportunities for strategic crossing of promising and complementary genotypes to increase favourable alleles for key agronomic, physiological and biochemical traits to improve drought adaptation and yield gains.…”

“…In tepary bean, seed yield is positively associated with NPPP and HSW under water‐limited condition (Kuruvadi & Valdez, 1993) and harvest index under non‐stressed condition (Mhlaba et al, 2018a). NSPP, NPPP, and HSW exhibit high BSH (>80) under drought stress conditions (Kuruvadi & Valdez, 1993).…”

“…Several studies have utilized common bean genomic resources for genetic analysis of tepary bean. For example, Blair et al (2012) and Mhlaba et al (2018a) determined genetic relationships of tepary bean species including P. acutifolius, P. tenuifolius and P. latifolius using SSR markers and reported extensive genetic differences. There are limited molecular resources developed for tepary bean.…”

“…Novel breeding strategies such as the development of multi‐parent advanced generation intercross (MAGIC) populations/lines are useful to combine favourable genes for tolerance to abiotic stresses (Bandillo et al, 2013; Huang et al, 2015; Huynh et al, 2018). Domesticated and genetically diverse tepary bean genotypes such as G40201, G40237, G40158, G40157, G40158, G40084 and G40033 (Mhlaba et al, 2018a) could be systematically hybridized to generate MAGIC populations. The rearrangement of alleles which occurs due to enormous recombination events in a MAGIC population could increase genetic diversity in the cultivated tepary bean.…”

Genotype-by-Environment Interaction in Tepary Bean (Phaseolus acutifolius A. Gray) for Seed Yield

“…Tepary bean shows wide genetic and morphological variation [16][17][18], with yield gains that can be above 2000 kg per hectare [19]. For example, Mhlaba et al [20] and Blair et al [21] revealed high genetic diversity in tepary bean using simple sequence repeats (SSR) markers. The genetic variability offers opportunities for cultivar development with the farmer and market-preferred desired traits.…”