Open resorce

While allocation of carbon to the developing wheat spike determines grain sink strength, concurrent growth of other plant organs (structural and non-structural dry matter; DM) competes for carbon. This study observed genetic variation in structural and non-structural DM partitioning to the true stem, leaf sheath and spike, and associations with spike growth, harvest index (HI), and grain yield in 26 CIMMYT cultivars and advanced lines under high radiation, irrigated conditions in northwestern Mexico during 2011-12 and 2012-13. Structural DM partitioning was assessed in the true-stem internodes and amongst the spike morphological components (rachis, glume, palea, lemma, awn) at harvest. Results showed a positive association between spike partitioning index (spike DM/above ground DM at anthesis + 7 days; SPI) and HI (R2 = 0.16, P< 0.05). Lower true-stem structural DM partitioning was associated with higher SPI and spike DM growth per unit area at anthesis + 7 days. There were negative associations between SPI and spike DM per unit area and true-stem internode 2 and 3 DM partitioning (P< 0.05), but no associations with other internodes. A positive linear association was determined between each of rachis specific weight (rachis DM per unit length) and DM partitioning to the palea and the fruiting efficiency (grains per unit spike DM at anthesis + 7 days). A Genome Wide Association Study (GWAS) is ongoing to identify genetic markers for these key target traits to enhance HI in the High Biomass Association panel at the field site in northwestern Mexico during 2015-16, as part of the PhD of Aleyda Sierra Gonzalez.

Wheat CRP FP3 - Global partnership to accelerate genetic gain in farmers field

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