Spike Fertility index in wheat: Trait performance under different crop growth conditions.

GONZALEZ FERNANDA G; TERRILE IGNACIO

Congreso; 6th International Crop Science Congress; 2012

World wheat demand will grow significantly in next decades thus global production needs to be increased. This increment could be achieved through more area under wheat cropping or increasing farm yields, which are highly associated to yield potential in a large range of environments. The study of ecophysiological attributes simpler than potential yield, but functional associated to this, and the understanding of the physiological and genetic basis would be a useful breeding tool to achieve higher genetics gains in wheat yield potential. The spike fertility index at harvest (SFIh grain number (chaff weight at harvest)-1) is strongly associated to potential grain number in recent wheat varieties released to the market in Argentina. Understanding the performance and stability of the SFIh under different crop growth conditions would help to determine its usefulness as breeding tool in the future. Three contrasting cultivars for SFI: Baguette Premium 11 (BP11), Baguette 19 (B19) both with high SFIh vs BIOINTA 2002 (Bio2002) with low SFIh were sown under three nitrogen doses (Ni, 130kgN.ha-1, 200kgN ha-1), two levels of incident radiation during stem elongation period (both with 200kgN ha-1) and two different sowing dates (early June and late July) during 2010 and 2011 cropping seasons. Grain number per square meter explained the yield variation between cultivars and different crop situation during both years (R2=81%, p<0.0001).The SFIh explained about 75% of differences observed in grain number between cultivars and crop growth conditions during both years of experiments (R2=75%, p<0.0001) showing the importance of the trait in the determination of this yield component. Cultivar by treatment interaction was not large (p=0.056), thus,  although SFIh values changed through crop environments (average of both years): 123.1 ±6.8 (BP11-200N); 148.7 ±24.7 (B19-200N); 84.8 ±17.3 (Bio2002-200N) and 130.6 ±17.0 (BP11-200NSha); 114.5 ±46.5 (B19-200NSha); 54.5 ±10.9 (Bio2002-200NSha) the cultivar ranking did not change significantly (except B19-200NSha).These results show the strong genotypic component of the trait and its potential use for breeding in the future.