ASSOCIATION OF PROTEIN POLYMORPHISM AMONG PEPPER (CAPSICUM-ANNUUM-L) INBRED LINES WITH AGRONOMIC PERFORMANCE OF THEIR CROSSES

The genetic variation of 10 morphologically similar pepper (Capsicum annuum L.) inbred lines has been analyzed by two-dimensional electrophoresis with immobilized pH gradient (IPG-DALT) of seed proteins. For all pairs of inbred lines genetic distance indices were calculated on the basis of the IPG-DALT analysis and a genetic tree was constructed. The protein polymorphism data of the 10 inbred lines were integrated into a pepper breeding program to validate the assumption that there is a higher chance of achieving better hybrid performance when the genetic distance between the parents is as great as possible. Field trials were performed in Turkey and consisted of a total of 27 crossings based on 9 inbred lines. Fifteen hybrids exceeded the crop yield of the better parent and 8 additional hybrids exceeded the mean crop yield of both parents. The genetic distance indices of the parental inbred lines based on protein polymorphism data were not significantly correlated to heterosis performance of the experimental hybrids (r = 0.20), indicating that protein polymorphism data add little to the prediction of single cross hybrid performance. Nevertheless, protein polymorphism data support the breeder in being more effective in finding out the best inbred combinations, because most of the less promising crossings can be omitted from the expensive and time-consuming performance tests. Those hybrids whose distance indices exceeded the mean of all 27 distance values (0.52) were superior to the mean value of all heterosis performances by 19%. Moreover, 11 out of 15 hybrids having distance indices higher than the mean of the 27 crossings exceeded the mean of all heterosis values (304 g), but only 5 hybrids out of 12 showing distance values below the mean exceeded the overall mean of heterosis performance. We conclude that IPG-DALT can be used as an efficient tool in vegetable hybrid breeding.