STUDY ON COMBINING ABILITY AND USE of SSR MARKER TO DETECT LG1 AND LG2 IN ERECT LEAF MAIZE INBRED LINES WITH MO17 AND B73 USING TESTER X LINE MATING DESIGN

Abstract

     The present study was conducted to evaluate the general combining ability effects in a selection of maize inbred lines for grain yield and leaf angle by using tester x line analysis under spring season conditions. Eight erect leaf maize inbred lines and two testers, Mo17 and B73, were crossed in tester x line scheme in the 2014 season. Sixteen testcrosses were evaluated in a randomized complete block design with two replications during the 2015 spring season. Results showed that the E2, E7 and E8 lines had leaf angles from 30^o to 35o and belong to the compact plant type while the remaining lines had leaf angles (LA) <30^o and belong to the erect leaf plant type. The leaf orientation value (LOV) analysis showed that the plant canopy had vertical leaf orientations in the all lines planted. We identified only one testcross (THL15) that had LA <30^o making it an erect leaf plant type, six testcrosses had LA >35^o making them normal plant types, and the remaining testcrosses belonged to the compact type. Estimates of general combining ability (GCA) effects for the eight inbred lines and the two testers showed that three inbred lines, E4, E7, and E8, and tester Mo17 had small a GCA for leaf angle. There were five inbred lines, E1, E2, E3, E4, and E6, and tester Mo17, that showed a positive GCA for grain yield. The primers umc1165 (for lg1) and bnlg1505 (for

lg2) were used to detect the target genes in the parental lines and testcrosses. Results showed that the primers gave PCR products with a high level of polymorphisms so that we could identify that lines and crosses contained lg1 and lg2 genes. This suggested that SSR markers could be applied to a MAS program to screen material with erect leaves in order to breed maize for planting in high densities.