General combining ability for field resistance to late blight in potato

Estimates of general combining ability of 19 potato parents were computed by the weighted least square analysis using data from greenhouse testing of field resistance to late blight in 32,552 seedlings from 28 crosses. SLB/P-9-12, Kufri Jyoti and SLB/R-11-10 were found to be the best parents for transmitting late blight resistance. Very high correlation of (r²⁶ = 0.83**) between the observed and fitted percentage of resistant seedlings in different aosses indicated that useful information can be obtained through this model about the promising parents for late blight resistance from the data which are otherwise rejected. However, significant χ² value indicated that specific combining ability between parents also contributed to the observed variation.