Combining ability of quality protein maize inbred lines for seedling tolerance to drought stress

Issue Date

8-2016

Abstract

Drought stress is a major constraint for maize seedlings in sub-Saharan Africa where temperatures can reach up to 40˚C following planting. Failure of the plant to withstand drought stress at seedling stage implies that there is a reduced crop stand, which translates to reduced yield. The objectives of this study were to estimate general combining ability (GCA) and specific combining ability (SCA) effects and gene action for morpho-physiological traits of quality protein maize (QPM) inbred lines subjected to seedling drought stress. Twenty-one QPM inbred lines were crossed using a North Carolina mating design II. Forty-five hybrids which produced enough seed were evaluated under optimum and stressed conditions. Three control hybrids were included to make 48 treatments. The inbred lines and 48 hybrids were planted under simulated drought stress conditions in polyvinyl chloride pipes at 25% and 75% of field capacity over 21 d in a randomized complete block design replicated 3 times. General combining ability accounted for a greater percentage of the treatment sum of squares, suggesting that additive gene action was more important than non-additive gene action for the expression of seedling traits under drought conditions. Inbred lines L2, L4, L16, and L18 were the best lines that exhibited high GCA effects, and were also parents to four of the five single crosses with the best SCA effects for most traits. As a result of their superior GCA and SCA effects under drought stress, these inbred lines are recommended for inclusion in QPM breeding programmes aimed at developing drought tolerant cultivars.

Source or Periodical Title

Philippine Journal of Crop Science

ISSN

0115-463x

Volume

41

Issue

2

Page

1-12

Document Type

Article

Frequency

tri-quarterly

Physical Description

tables, graphs

Language

English

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