A yield architecture frame work to explain adaptation of pearl millet to environmental stress.

Oosterom, E.J. van and Bidinger, F.R. and Weltzien, E.R. (2003) A yield architecture frame work to explain adaptation of pearl millet to environmental stress. Field Crop Research, 80 (1). pp. 33-56.

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Functional Knowledge of the physiological basis of crop adaptation to stress is a prerequisite foe exploiting specific sadaptation to stress environments in breeding programs.This paper presents an analysis of yield components for pearl millet,to explain the specificadaptation of local landrace to stress environments in Rajasthan,India.Six genotypes,ranging from high-tillering traditional landrace to low-tillering open-pollinated moderncultivars,were grown in 20 experiments, covering a range of non-stress and drought stress patterns. In each experiment,yield components(panicle number,grain number,100 grain mass)were measured separately for main shoots,basal tillers, and nodal tillers. Under optimum condtions, landrace had a significantly lower grain yield than the cultivars, but no significant differences were observed at yield levels around 1 ton ha-1.This genotypeX environment interaction for grain yield was due to a difference in yield strategy, where landraces aimed at minimising the risk of a crop failure under stress conditions,and modern cultivars aimed at maximising yield potential under optimum conditions. A key sapect of the adaptation of landraces was the small size of the main shoot panicle, as it minimised (1)the loss of productive tillers during stem elongation; (2) the delay in anthesis if mid-season drought occures;and (3) the reduction in panicle productivity of the basal tillers under stress.In addition, a low investment in structural panicle weight,relative to vegetative crop growth rate, promoted the production of nodal tiller,providing a mechanism to compensate for reduced basal tiller productivity if stress occured around anthesis.A low maximum 100 grain mass also ensured individual grain mass was little affected by environmental conditions.The strategy of the high-tillering landraces carries a yield penalty under optimum conditions, but is expected to minimise the risk os a crop failure, particularly if mid-seasondrought stress occures.The yield architecture of low-tillering varieties,by contrast,will be suited to end-of-season drought stress,provided anthesis is early.Application of the above adaptation mechanisms into a breeding program could enable the identification of plant types thatmatch the prevalent stress patterns in he target environments. U

Item Type: Article
Author Affiliation: International Crops Research Institute for the Semi-Arid Tropis (ICRISAT),Patancheru 502 324 Andhra Pradesh, India
Subjects: Atmosperic Science > Climatology
Divisions: Millet
Depositing User: David T
Date Deposited: 14 Jul 2011 09:59
Last Modified: 14 Jul 2011 09:59
URI: http://eprints.icrisat.ac.in/id/eprint/2246

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