The 10th Asian Crop Science Association Conference

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Oral sessions

Crop Genetics and Physiology » O41: Genetic Improvement of Crop Yield

[O41] Genetic Improvement of Crop Yield

Thu. Sep 9, 2021 9:45 AM - 11:45 AM Room 4 (Oral) (Crop Genetics and Physiology)

Chair: Taichiro Ookawa (Tokyo University of Agriculture and Technology, Japan )
Chair: Hiroshi Fukayama (Kobe University, Japan)
Chair: Masahiro Kishii (International Maize and Wheat Improvement Center, Mexico)
Chair: Shunsuke Adachi (Tokyo University of Agriculture and Technology, Japan )

9:45 AM - 10:05 AM

[O41-01] Physiological Traits to Breed for Yield Potential

(Invited Speaker)

○Matthew Reynolds, Gemma Molero, Carolina Rivera-Amado, Francisco Piñera-Chavez, Francisco Pinto, Margaret Krause, Liana Acevedo, Sivakumar Sukumaran (International Maize and Wheat Improvement Center, Mexico)

Boosting yield potential considers increasing net photosynthesis (source) and improving partitioning of photo-assimilates to grain (sink). Genetic variation in radiation use efficiency is observed in advanced wheat lines, and unimproved genetic resources. Research to boost photosynthesis per se considers several traits. Slow adjustment of photosynthetic efficiency during shade-sun transitions can cost 20% of potential carbon uptake. Genetically diverse wheat lines showed that natural variation in adjustment was correlated with final yield. Boosting spike photosynthesis (SP) represents an untapped opportunity to improve canopy photosynthesis since spikes intercept ~40% of incident light. Among elite lines, genetic variation in SP contribution to yield ranged from 20-50%. More optimal light and N distribution in crop-canopies can theoretically boost RUE; field research showed that lines with more evenly distributed chlorophyll in the upper three leaves express higher yield and biomass and explained >20% RUE variation. Several traits determine sink-strength. Stem middle internodes 2 and 3 grow at the same time as developing spikes, effectively competing for assimilate. Genetic variation for these internodes was associated with increased grain number without reduction in plant height in elite lines. Fruiting efficiency –grain number/dry weight of spike at flowering- was also associated with sink strength and yield. Lodging is common at high yield; significant variation for stem and anchorage strength exists in elite lines, indicating breeding targets. Pre-breeding to boost yield potential used strategic crosses to complement source and sink traits. Yield advantage of best progeny over CIMMYT checks has been up to 8% across international target environments.