Selection Improves Drought Tolerance in Tropical Maize Populations: I. Gains in Biomass, Grain Yield, and Harvest Index

Edmeades, G.O. and Bolanos, J. and Chapman, S.C. and et al, . (1999) Selection Improves Drought Tolerance in Tropical Maize Populations: I. Gains in Biomass, Grain Yield, and Harvest Index. Crop Science, 39 (5). pp. 1306-1315.

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Drought is common in tropical environments, and selection for drought tolerance is one way of reducing the impacts of water deficit on crop yield. The primary objective of this study was to evaluate biomass, grain yield, and harvest index of maize (Zea mays L.) populations selected for drought tolerance. Three late-maturing tropical maize populations were subjected to three cycles of S 1 recurrent selection (`La Posta Sequı́a' and `Pool 26 Sequı́a') or eight cycles of full-sib recurrent selection (`Tuxpeño Sequı́a') for yield and traits indicative of drought tolerance during flowering and grain filling. Selection gains were assessed in five trials conducted under mid–late season drought and in five trials conducted under well-watered conditions. In water-stressed environments, with average yields of 1.0 to 4.5 Mg ha−1, yield gains averaged 0.26 Mg ha−1 (12.6%) cycle−1 for La Posta Sequı́a and Pool 26 Sequı́a and 0.08 Mg ha−1 (3.8%) cycle−1 for Tuxpeño Sequı́a. In well-watered conditions, where mean yields ranged from 5.8 to 10.4 Mg ha−1, corresponding gains per cycle were 0.12 Mg ha−1 (1.5%) and 0.04 Mg ha−1 (0.5%). Total biomass was unaffected by selection. Mean correlated responses to selection observed under drought were −0.11 Mg ha−1 cycle−1 in stem biomass and 0.025 cycle−1 in harvest index (HI), and under well-watered conditions, 0.005 cycle−1 in HI. Stem biomass and HI were negatively correlated under drought ( r = −0.57; P < 0.01) Improved drought tolerance was attributed to simultaneous selection in well-watered environments and under carefully managed water stress at flowering, resulting in greater partitioning of biomass to the ear and increased harvest index.

Item Type: Article
Uncontrolled Keywords: Tropical Maize Populations, Zea mays L.
Author Affiliation: Pioneer Hi-Bred International, Inc.,
Subjects: Crop Improvement > Seed Technology
Divisions: Maize
Depositing User: Mr Arbind Seth
Date Deposited: 21 Nov 2012 11:19
Last Modified: 21 Nov 2012 11:19
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