Genetic analysis and molecular mapping of seedling survival drought tolerance gene in lentil (<Emphasis Type="Italic">Lens culinaris</Emphasis> Medikus)

Lentil populations were developed from crosses between ‘JL-3’ (sensitive to drought stress) and ‘PDL-1’ and ‘FLIP-96-51’ (tolerant to drought stress), to study the inheritance of drought tolerance and to identify the markers associated with it. The parental types, F₁, F₂, F₃, and backcross (BC) generations were screened for drought tolerance using seedling survivability and drought scores. The F₁ hybrids responded similar to the drought-tolerant parent, indicating dominance of seedling drought tolerance over sensitivity. Segregation for seedling survival drought tolerance versus sensitivity in F₂ generation was in complete agreement with monogenic 3:1 ratio. The F₃ families and backcross data additionally confirmed monogenic tolerance based on seedling survival under drought. Out of 51 SSR markers screened, thirteen markers were polymorphic between the parental types. Seven markers among them were found to be associated with seedling survival drought tolerance through bulk segregant analysis. Association of these markers with seedling survival drought tolerance was further confirmed through their screening on 10 drought-tolerant and drought-sensitive genotypes. These seven markers were screened in F₂ mapping population (JL-3 × PDL-1) of 101 individuals to map their position in relation to the gene for seedling survival drought tolerance. Linkage analysis mapped the seven markers within a map distance of 133.2 cM. A single major gene Sdt was identified with a LOD value of 19.9 and phenotypic variation (R ²) of 69.7 %. The Sdt locus was obtained in the marker interval of PLC_105–PBA_LC_1480 spanning 24.9 cM with the closest marker PLC_105 at a distance of 9.0 cM on the obtained linkage group. This is the first report on genetic control and linkage of SSR markers for drought tolerance in lentil. These linked markers can be used in molecular breeding programmes for introgression of seedling survival drought tolerance gene in high-yielding cultivars.