Induction of Fusarium wilt (Fusarium oxysporum f. sp. pisi) resistance in garden pea using induced mutagenesis and in vitro selection techniques.

Wilt caused by Fusarium oxysporum f. sp. pisi is a serious production constraint for peas worldwide. An attempt was made to isolate wilt-resistant mutants in two susceptible pea genotypes, Arkel and Azad P-1, employing induced mutagenesis and in vitro selection techniques. Two thousand seeds of each genotype were mutagenized either with ethyl methane sulfonate (EMS, 0.2% and 0.3%) or gamma rays (5-22.5 kR) in 60Co gamma cell for three consecutive years. Screening of different mutagenized populations under wilt-sick plots resulted in the isolation of 25 mutants exhibiting complete or enhanced wilt resistance compared to parental genotypes. Five of these wilt-resistant mutants also outperformed the susceptible background genotypes in terms of yield and other horticultural traits. Efforts were also made to isolate wilt-resistant regenerants from callus cultures exhibiting insensitivity to culture filtrate (CF) of F. oxysporum f. sp. pisi. A total of 250 regenerants (R 0) were obtained from CF-insensitive calli selected from medium supplemented with 20% culture filtrate. When evaluated in artificially inoculated sick plots, only five R 2 lines obtained from the regenerants exhibited enhanced wilt resistance compared to parental cultivars. However, the selected lines did not exhibit resistance levels equivalent to those shown by wilt-resistant lines isolated through in vivo mutagenesis. To conclude, induced mutagenesis through irradiation and EMS treatments exhibited superiority over in vitro selection for inducing wilt resistance in peas.