Phenology, biomass and fertil florets in high Yielding cultivars adapted to the north of Buenos Aires, Argentina.

GONZALEZ FERNANDA G; TERRILE IGNACIO; CARP ANDRES

Workshop; II Workshop Internacional de Ecofisologia de Cultivos aplicada al mejoramiento vegetal.; 2013

Wheat yield potential has to increase during the next decades. Studying the variation in crop physiological traits associated to yield potential in modern high yielding cultivars may help to improve genetic gains in yield potential in the future. Sixteen high yielding cultivars (including early ?EC- and late cycle ?LC- to anthesis) were sown at the Experimental Field Station of Pergamino, INTA, under potential growing conditions (high fertilization, irrigation and pest and weeds controlled). The plots (7 rows, 0.2m apart and 5 m long) were arranged in RCBD with three replications. The time to anthesis and the sub-phases (emergence -1 node ?E-1N-, and 1 node - anthesis -1N-AT- which includes the spike growth period) were determined and the thermal time (ºCd, tb=0ºC) was calculated. The biomass produced at anthesis, and the partitioning to the spikes, were estimated together with the number of fertile florets produced. Time to anthesis ranged from ca 1.000 to 1.400ºCd considering all cultivars. Time to anthesis was highly associated not only to duration of E-1N (r2= 91% p<0.0001) but also to duration of 1N-AT (r2= 47% p<0.005), considering all cultivars. Duration of E-1N and 1N-AT were different (p<0.005) among cultivars within the same cycle to anthesis (EC or LC). Duration of 1N-AT was associated with spike biomass at anthesis, only for cultivars with similar spike growth rate. The number of fertile florets produced at anthesis differed among LC cultivars (p<0.05) but was similar among EC cultivars. The variation of fertile florets at anthesis was associated with the spike biomass at anthesis only for cultivars with similar spike fruiting efficiency (FE). There is available variation in modern elite wheat cultivars in 1N-AT and FE, two traits highly associated to yield potential.