Towards the Reliable Prediction of Time to Flowering in Six Annual Crops. VI. Applications in Crop Improvement

Abstract

Variation in time from sowing to flowering (/) was examined for 44 cultivars of soyabean, mungbean, black gram, ricebean, cowpea, chickpea, lentil and barley, when grown in up to 21 diverse environments obtained by making one or more sowings at each of six locations spanning tropical, sub-tropical and temperate climates in Australia. The utility of simple linear models, relating rate of development (1//) towards flowering to mean photoperiod and temperature prevailing between sowing and flowering, was evaluated. The models were highly efficient, explaining most (86.7%) of the variation observed across species, cultivars and environments. They were particularly efficient in describing responses where cultivars were relatively welladapted, in agronomic terms, and least efficient where cultivars were exposed to unfavourable temperature and, to a lesser extent, photoperiod. Opportunities for exploiting the models in applied crop improvement include their use in interpretation of G X E interaction, genotypic characterization and selection of parental genotypes, selection of test environments, designing screening procedures, and more efficiently matching genotypes to target environments. The main strengths of these linear, additive rate models in crop improvement are their wide applicability across species and genotypes, their relative simplicity, and the requirement for few genotype-specific response parameters. Their main weakness is their lack of precision in describing responses when plants are exposed to unfavourable photothermal extremes, albeit in circumstances that are sometimes unrealistic for cropping those particular genotypes.Predicciones del tiempo que ha de transcurrir hasla la flotation. VI. . 90 R. j . LAWN et al. RESUMENSe examinaron las variaciones en tiempo entre la siembra y la floracion de cuarenta y cuatro cultivos de sqja, vigna mungo, vigna radiata, arroz, caupi, garbanzos, lentejas y cebada cuando se cultivaban en 21 ambientes diferentes, obtenidos mediante la practica de una o mas siembras en cada una de las seis ubicaciones-que iban de tropicales y subtropicales a climas templados en Australia. Se evaluo la utilidad de modelos lineales simples, que relacionan la velocidad de desarrollo (1/f) hacia la floracion con el fotoperiodo y la temperatura predominante medios entre la siembra y la floracion. Los modelos fueron altamente eficaces, explicaron la mayon'a (86,7%) de las variaciones observadas en las distintas especies, cultivos y ambientes. Fueron particularmente eficaces para describir rcacciones donde los cultivos sc habian adaptado relativamente bien, en terminos agronomos, y menos eficaces donde los cultivos habian sido expuestos a temperaturas desfavorables y en menor medida, a fotoperiodos desfavorables. Las oportunidades de explotacion de los modelos en mejoras aplicadas de los cultivos incluyen su uso en la interpretation de la interaction G X A, la caracterizacion genotipica y la seleccion de genotipos padres, la seleccion de ambientes de prueba, el disefio de procedimientos de cri...

Abiotic Stresses

“…Thus changes in phenology will change the risk of exposure to frost, drought and high and low temperatures during sensitive growth stages. The timing of flowering is a particularly important event as it determines the duration of the vegetative phase (sowing to flowering), which establishes the potential of the crop, and at the same time determines the climatic conditions that the crop will be exposed to during reproductive growth (Lawn et al 1995). Temperature has a major influence on the general adaptation of lentils but extremes in temperature during the growth and reproduction of lentils can result in a more specific and dramatic effect.…”

Rates of Progress towards Flowering and Podding in Bambara Groundnut (Vigna subterranea) as a Function of Temperature and Photoperiod

“…A relatively simple method, developed at the University of Reading, uses linear equations to relate the rate of progress * E-mail Martin.Brink!USERS.AGRO.WAU.NL from sowing to flowering (calculated as the inverse of the duration from sowing to flowering) to the mean preflowering photoperiod and temperature (Hadley, Summerfield and Roberts, 1983 b ;Summerfield et al, 1991 ;Lawn et al, 1995). The main advantages of this method are that the responses to photoperiod and temperature become linear and that interactions between temperature and photoperiod influences often disappear (Summerfield et al, 1991).…”

Progreso en el programa nacional español de mejora de cebada

“…This study will focus on grain yield, the main target of the breeding program, but also on its relationship with flowering date. Flowering date is one of the most important traits for improving crop productivity and adaptation (Lawn et al, 1995;Laurie, 2009;Brachi et al, 2010), and is a primary objective of all breeding programs around the world.…”