More fertile florets and grains per spike can be achieved at higher temperature in wheat lines with high spike biomass and sugar content at booting.

MF DRECCER; KB. WOCKNER; JA PALTA; CL MCINTYRE; MG BORGOGNONE; M BOURGAULT; M REYNOLDS ; MIRALLES D.J

FUNCTIONAL PLANT BIOLOGY

CSIRO PUBLISHING

Lugar: Collingwood; Año: 2014 vol. 41 p. 482 - 495

1445-4408

An understanding of processes regulating wheatfloret and grain number at higher temperatures is required to better exploit genetic variation. In this study we tested the hypothesis that at higher temperatures, a reduction infloret fertility is associated with a decrease in soluble sugars and this response is exacerbated in genotypes low in water soluble carbohydrates (WSC). Four recombinant inbred lines contrasting for stem WSC were grown at 20/10
C and 11 h photoperiod 5 until terminal spikelet, and then continued in a factorial combination of 20/10
C or 28/14
C with 11 h or 16 h until anthesis. Across environments, high WSC lines had more grains per spike associated with moreflorets per spike. The number of fertile florets was associated with spike biomass at booting and, by extension, with glucose amount, both higher in high WSC lines. At booting, high WSC lines had higherfixed 13 C and higher levels of expression of genes involved in photosynthesis and sucrose transport and lower in sucrose degradation compared with low WSC lines. At high temperature, the intrinsic rate of 10 floret development rate before booting was slower in high WSC lines. Grain set declined with the intrinsic rate offloret developmentbefore booting, with an advantage for high WSC lines at 28/14
Cand 16 h. Genotypic and environmentalaction onfloret fertility