Molecular mapping of popping volume QTL in popcorn ( Zea maize L.)

Popcorn (Zea mays L.) is a special type of maize that pops up when heated leading to high flake volume. It is being used as a popular fiber-rich and nutritious snack all over the world. The genetic control of the popping rate and flake volume is not well understood. The cross made between high popping volume inbred line as the female parent and low popping volume composite as the male parent. The F2 population of 504 plants showed continuous variation for popping volume signifying that the popping volume is a quantitative trait governed by multiple genes. Only a set of 126 out of 313 maize SSR markers were successfully amplified using the standard PCR reaction and 66 among these were found polymorphic between the two parents. Bulk segregant analysis (BSA) of F2 plants based on F2:3 seeds were carried out for mapping popping volume QTL using the 66 polymorphic SSR markers. Only four markers showed an association with popping volume in BSA. Out of the four, three SSR markers (bnlg1331, bnlg1520, bnlg1144) showed high association with the popping volume data after de-bulking of the positive and negative plants used in the bulks. All the 504 F2 plants were genotyped using 3 SSR markers and the F2:3 seeds were phenotyped for popping volume. The single marker analysis of the F2 plants showed that the 3 SSR markers bnlg1331, bnlg1520, and bnlg1836 on chromosome 1, 2, and 5, respectively, were closely associated with the QTL for popping volume covering 78% of total phenotypic variance.