Genetics of rust resistance in mutants and interspecific derivatives of groundnut (Arachis hypogaea L.)

摘要

Rust is the major foliar disease limiting yield and quality in groundnut. Mutants and interspecific derivatives are important sources of resistance to rust. Crosses involving mutants and inter-specific derivatives viz., crosses involving mutants (VL 1, 28-2, 45, 45 (S) and 110) and inter-specific derivatives (ICGV 87165, D 39d and B 37c), viz., 110 × VL 1, 45 × 45 (S), VL 1 × ICGV 87165, 110 × ICGV 87165, 28-2 × D 39d, 28-2 × B 37c and B 37c × D 39d were made to discern the genetic basis of rust resistance. Mutant VL 1 was resistant while mutants 28-2, 45 and 110 were susceptible to rust. Interspecific derivatives, ICGV 87165, D 39d and B 37c were resistant to rust. All the hybrids (F1’s) showed moderately susceptible (S) reaction indicating partial dominance nature of genes governing resistance (R). Segregation in F2 revealed involvement of duplicate recessive genes in both the mutants and interspecific derivatives conditioning rust resistance. F3 breeding behaviour confirmed the proposed segregation ratios. Four-locus model was proposed to formulate the genotypic constitution of the parents based on genetic hypotheses. Further, independent recessive genes governed rust resistance in mutational and inter-specific sources.