Inheritance of resistance of two pea lines to powdery mildew

The GRICAND, Andean Crops Research Group has identified two resistant pea (Pisum sativum L.) lines to powdery mildew (PM) (Erysiphe pisi): ILS6527 (resistance of foliage and pods) and UN6651 (pods only resistance). This study established the inheritance of these two distinct PM-resistance genotypes. Resistant lines ILS6527 and UN6651 were crossed with two susceptible varieties (Andina and San Isidro) and their respective generations (F-1, F-2, BCr, and BCs) were evaluated for PM resistance in naturally infected field tests. Data were subjected to chi-square (chi (2)) and homogeneity test. The two crosses of ILS6527 segregated in a monogenic Mendelian ratio of 3 susceptible: 1 resistant in F-2 generation, and 1 susceptible: 1 resistant ratio in BCr, which indicate a recessive control of resistance. The resistance gene in ILS6527 may be allelic with er-1. UN6651 exhibited PM resistance only in pods, the F-2 and backcrosses from the crosses with UN6651 segregated in a manner indicative of recessive resistance.