Mega-environment differences affecting genetic progress for yield and relative value of component traits

Vega, A.J. de la and Chapman, S.C. (2010) Mega-environment differences affecting genetic progress for yield and relative value of component traits. Crop Science, 50 (2). pp. 574-583.

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Large and regional genotype × environment interactions can be a major impediment to sunflower (Helianthus annuus L.) genetic progress in Argentina, where yield improvements have slowed since the mid-1990s. Previous studies in the central subregion show that oil yield gains were aintained for the last 20 yr and contributed to counteracting a decline in agronomic quality of the sunfl ower area. In this study, mixed models, quantile regression, and pattern analyses were applied to three long-term (18 yr) multienvironment datasets (67 sites) to show that: (i) in high-yielding hybrids, oil yield has increased linearly by 6.7, 10.5, and 6.2 kg ha–1 yr−1 over 25 yr in the northern, central, and southern subregions, respectively; (ii) selection for specific adaptation to the central region did not improve oil yield in northern environments (consistent with previous pattern analysis–based predictions), nor in the southern region, suggesting that the south is a third mega-environment; (iii) the central subregion had the greatest, most consistent genetic gain; (iv) while the relative regional responses of hybrid groups were similar for oil concentration and grain yield, there was strong hybrid × region crossover for relative responses of time to fl owering; and (v) the merger of the original gene pools via breeding for oil yield reduced the original range on phenological responses within subregions and produced different maturity types for each region.

Item Type: Article
Author Affiliation: Advanta Semillas S.A.I.C., Ruta Nac. 33 Km 636, C.C. 559, 2600 Venado Tuerto, Argentina
Subjects: Plant Production
Crop Improvement > Genetics/Genomics
Divisions: Other Crops
Depositing User: Sandhya Gir
Date Deposited: 02 Jan 2011 21:12
Last Modified: 02 Jan 2011 21:12
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