Heterosis and Inbreeding Depression in Five Commercial Hybrids and an Open- Pollinated Variety of Maize

Date

3-1990

Degree

Bachelor of Science in Agriculture

Major Course

Major in Agronomy

College

College of Agriculture and Food Science (CAFS)

Adviser/Committee Chair

Danilo P. Baldos

Abstract

Six corn cultivars, their crosses and selfed seeds were evaluated in an experiment conducted at UPLB from December 1988 to September 1989 to determine the degree of inbreeding depression and heterosis for yield and other agronomic characters.

Results showed that there are significant differences among the three groups in all the traits measured except for shelling percentage. The F1’s and the cultivar crosses differed significantly from F2’s which have lower means dew mainly to the effect of selfing.

Grain yield, stand count and moisture content of F1’s exhibited significant differences which indicated yield potential, vigor and maturity, respectively. F2’s on the other hand, differed significantly in plant height, percent prolificacy, ear characteristics and moisture content.

Among crosses, significant differences were found only in plant height, ear length and weight. Those particular crosses that exhibited the highest values came from the best performing hybrids.

In general, were is very little heterosis present on the mean yield performance as well as the other traits except for stand count. The degree of heterosis of the two commercial hybrids, P3228 and CS 757, crossed with IPB var 1, an OPV, obtained significant yield increase. This indicates the possibility of utilizing the two hybrids in improving the performance of the OPV. It could also be used as inbreds for hybrid breeding development.

A significant yield reduction was observed in the F2’s. The degree of inbreeding depression, however, was less in the commercial hybrids SMC and P3228 with an average yield loss of about 37% of the F1 potential. Thus, corn farmers can still utilize F2 seeds from the two hybrids to plant the next crop. Yield reduction in OPV was likewise significant but may be lower since farmers usually practice selection.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 993.5 1990 A42 M55

Document Type

Thesis

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