engleski

Impacts of testing environments and crop density on winter wheat kernel weight

Selection of stabile genotype with broad adaptation to various environments is one of the main goals in winter wheat breeding. Genotype x environment interaction (GEI) hinders selection of the best genotypes due to confounding results for the genetic differences between wheat genotypes. Therefore, attention has been devoted to analyzing genotype by environment interactions (GEI) to improve crop breeding success (Thomason and Philips, 2006). Usually, strategy for selection of winter wheat is that selection should be made on several locations different in climatic and soil conditions. The objectives of this paper were to examine influence of different testing environments and sowing rates on formation of winter wheat thousand kernel weight and, after the stability analysis, to identify most stabile genotypes and locations. Thousand kernel weight is very important trait for yield formation in winter wheat and it is considered to be one of the direct yield component. Research work was conducted during 2006/07 growing season on four test locations with four different soil types: Nova Gradiška – fluvisol ; Osijek – eutric cambisol ; Požega – pseudogley ; Tovarnik – chernozem. Research work included 14 winter wheat genotypes. Genotypes were chosen due to their high yielding performance and good quality. They included recognized cultivars and new breeding lines. The examined genotypes were sowed with two sowing rates: 300 and 600 germinable seeds m-2. Combined analysis of variance showed highly significant (p≤ 0.01) influence of genotypes, environments (sowing rate and location) and GEI on thousand kernel weight. AMMI 1 model biplot showed that the location with highest thousand kernel weight in combination with lower sowing rate was Nova Gradiška. The most stabile location in combination with lower sowing rate and high thousand kernel weight was location with the best soil conditions – Tovarnik. Lower sowing rate at all locations showed higher thousand kernel weight than higher sowing rate at the same location. Lower sowing rate at all locations also was more stabile than higher sowing rate. Biplot also showed that locations were spread from locations with lower thousand kernel weight to locations with high kernel weight. That is very important for selection of stabile and adaptable genotypes. Examined genotypes differed in thousand kernel weight and in stability across environments. Breeding line OSK 63/05 has the highest thousand kernel weight, but it was unstable and adapted to higher yielding environments. Stabile genotypes, but with lower kernel weight, were cultivar Srpanjka and breeding line OSK 89/05. Best combination of high kernel weight and good stability was in breeding line OSK 108/04.

testing environments ; winter wheat ; AMMI ; 1000 kernel weight ; GEI

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