Wall, P.C.

Rendimiento y el cociente fototérmico: Una relación inevitable? - La Estanzuela (Uruguay) INIA|CIMMYT : 1998 - Printed

A strong relationship exists between the yield of wheat and the number of grains per unit area under diverse climatic conditions. This component is determined during the spike growth stage and fertilization and fixation of flowers before and immediately after the flowering. There is also a good relationship between the number of grain per m2 and the weight of the spikes per m2 at the flowering. The spike growth depends on the rate of the plant growth which, in turn, depends on the solar radiation and the partitioning of the carbohydrates in different growth organs at the same stage. The organ that exercises the primary competition on the spike is peduncle, even though the competition also comes from the accumulation of the carbohydrates, probably as reserves, to insure a good grain filling in case the conditions turn adverse. The weight of the spike at flowering depends as much on the rate of growth as on the duration of this stage, which is determined primarily by the temperature and lasts approximately 350 degrees/day. Due to the effects of the radiation and temperature on the spike growth and consequentially on yield, it is not surprising to see a very strong relation between the potential yield of wheat (without limitations of water, nutrients, diseases, insects or weeds) and the Photothermal Coefficient (the relation between the solar radiation and the mean temperature) during the month immediately before the crop flowering. As a result, the question that faces the breeders is if this relationship is inevitable or can be modified? Some principal venues open to the geneticists are analyzed in order to change and reach a new level of relation Yield: Photothermal coefficient.


Injurious factors
Plant response
Research projects
Variety trials
Yield increases


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Centro Internacional de Mejoramiento de Maíz y Trigo (CIMMYT) © Copyright 2015. Carretera México-Veracruz. Km. 45, El Batán, Texcoco, México, C.P. 56237.
Si tiene cualquier pregunta, contáctenos a CIMMYT-Knowledge-Center@cgiar.org