Genetic evidence for gametophytic selection of wilt resistant alleles in chickpea

Abstract

Gametophytic selection can drastically reduce the number of selection cycles during crop improvement programs. The objective of the present investigation was to test whether the nature of inheritance of two unlinked disease-resistant loci, h(1) and h(2), against Fusarium wilt in chickpea (Cicer arietinum L.) under gametophytic (pollen) selection was similar to that already observed at sporophytic level. A homozygous dominant (H(1)H(1)H(2)H(2)) susceptible genotype JG-62 was crossed to a recessive (h(1)h(1)h(2)h(2)) resistant genotype WR-315 to produce 20 F(1) hybrid seeds. In the following generation, flower buds of 10 F(1) hybrid plants were subjected to toxin stress before anthesis and the remaining ten control F(1) plants' flowers were sprayed with water. Thirty-four selected BC(1) plants were generated by test crossing resistant WR-315 individuals with pollen from toxin-stressed F(1) individuals. Both control and treated F(1) plants were selfed to produce respective F(2) generations. Two DNA markers, CS-27(700bp) and A07C(430bp), linked to susceptible alleles H(1) and H(2), respectively, were used to study the inheritance patterns of h(1) and h(2) loci in the F(2) and BC(1) generations. One hundred and forty-four selected F(2), 129 control F(2), and 34 selected backcross individuals were tested for the presence or absence of DNA markers. Except for the control F(2), observed ratios of selected F(2) and BC(1) populations exhibited significant chi-square deviations from expected monogenic and digenic ratios. Our results suggest that gametophytic selection is as effective as that realized at the sporophytic level, and that the gametophytic selection can be an effective breeding tool for plant breeding programs.

Early embryo achievement through isolated microspore culture in Citrus clementina Hort. ex Tan., cvs. ‘Monreal Rosso’ and ‘Nules’

“…This strategy would allow early genotype screening for selection of desirable alleles on pollen grains (Clegg et al, 1978; Hormaza and Herrero, 1996; Ravikumar et al, 2007). With respect to the sporophytic selection, the MGS has advantages for selecting among very high numbers of haploid individuals in a small space (Soleimani et al, 2010), allowing selection also of recessive characters and mutations, without the interference of dominance.…”

In vitro selection of yellow passion fruit genotypes for resistance to Fusarium vascular wilt

“…In vitro selection can be used with cultures derived from somatic tissues, cell suspension cultures, microspores or anther cultures (Jan et al 1993). In the later case, selection can be advantageous since resistant plants can be selected during initial growth stages employing toxins as in vitro selective agents, which drastically reduces the number of selection cycles made by crop improvement programs (Ravikumar et al 2007). Sometimes, a high correlation between in vitro and in vivo resistance to pathogenic fungi has been found by the regeneration capability of calli in the presence of culture filtrates (Thakur et al 2002;Kumar et al 2008).…”

Genetic evidence of pollen selection mediated phenotypic changes in maize conferring transgenerational heat‐stress tolerance

“…The selected (G) and control (C) F 2 populations with parents evaluated under pollen heat stress at UASB clearly indicated that the pollen selection for heat stress in F 1 has resulted in increased frequency of tolerant plants in selected F 2 populations vs. no pollen selection in F 1 of the same cross with respect to heat‐stress‐tolerant‐related traits. Such positive influence of pollen selection for heat stresses from the differential response of the pollen grains with reference to fertilization could be due to allelic differences in the pollen grains (Ravikumar, Patil, Soregaon, & Hegde, 2007). The effect of pollen selection for biotic and abiotic stress tolerance is clearly visible at the sporophytic stage of plants (Ravikumar et al., 2007; Ravikumar, Patil, & Salimath, 2003; Sacher, Mulcahy, & Staples, 1983; Totsky & Lyakh, 2015).…”

“…The subsequent progeny will be more tolerant to heat stress (Singh et al., 2016). The inheritance of traits selected through gametophytic tolerance has been demonstrated in chickpea ( Cicer arietinum L.) against Fusarium wilt and cold tolerance (Clarke et al., 2004; Kron & Husband, 2006; Ravikumar et al., 2007). The evaluation of the correlated response to the gametophytic selection has allowed the detection of significant variation for many sporophytic traits and the variation transmitted from generation to generation (Landi et al., 1989).…”

“…F I G U R E 4 Distribution pattern of three F 3 populations (GG, GC, and CC) of maize for seed yield and their components under stress condition (dash line represent the mean values, dots represent the outliers) stage of plants (Ravikumar et al, 2007;Ravikumar, Patil, & Salimath, 2003;Sacher, Mulcahy, & Staples, 1983;Totsky & Lyakh, 2015).…”