STUDY ON COMBINING ABILITY AND HETEROSIS IN MAIZE (Zea mays L.)

Abstract

The experimental was conducted at the Plant Breeding Research Field, Hajee Mohammad Danesh Science and Technology University during March, 2017 to May, 2018. Three testers and nine lines were crossed in all possible combinations and twenty seven hybrids were produced. The ratio of line: tester was 2:1 in the field. The lines were tasseled just after complete emergence to protect self-pollination or inbreeding. Therefore, pollens were available in both direction to successfully complete the crossing program. Before pollination, the silky stigmas were slightly cut to concurrent emergence and covered with brown paper bag. The pollens were collected from the tester tassels in brown paper bag and dusted on the silky stigmas regularly. The hybrid cobs were collected to grow in the next season. The hybrids were tested for eleven characters like plant height (cm), cob height (cm), cob length (cm), cobs per plant, cob diameter (cm), kernel rows per cob, kernels per row, and kernels per cob, cob weight per plant, 110- kernel weight and yield per plant (g). The general combining ability (gca) of the parents (lines and testers) and specific combining ability (sca0 for the hybrid combinations were estimated. The ANOVA revealed significant variation for all characters under study. The lines x Testers exerted maximum contribution to attained differential response of the hybrids. Since, lodging at maturity and grain size are the predominant characters along with yield per plant, so plant height at maturity and 100- kernel weight revealed suitable cross combinations. The desirable combinations for lodging resistance were ML21 x ML5, ML21 x ML12, M and 21 x ML 15 as projected by their negative and significant sca effects but only a single combination ML3 x ML5 showed significant and positive sca effect. Both heterosis over better parent and sca effects were simultaneously considered to select the outstanding cross combinations. Accordingly, ten hybrid combinations showed positive and significant sca effects for yield per plant but the simultaneous combination of heterosis , it is noted that three hybrids combinations such as, ML 21 x ML30, ML3 x ML30 and ML 21 x ML15 were found to be superior than the other hybrid combinations. Since the farmers of our country prefer single cross hybrids more, the outstanding three cross combinations may be launched with a view to release commercial hybrids for the farmers of our country.