Do mutations modifying the leaf area (nr3) and the number of potential seeds (dfc) influence photosynthetic gas exchange characteristics in common buckwheat Fagopyrum esculentum Moench?

Abstract

Contemporary buckwheat breeding in Russia is based mainly on a Mendelian mutation det. Some additional mutations are being considered for inclusion in buckwheat breeding programs. Among them are the nr3 (narrow leaf 3) and dfc (determinate floret cluster). We evaluated the effects of the mutations on both the characteristics of photosynthetic gas exchange and the number of seeds per plant. The nr3 reduces the leaf surface area by 1.4 times. The mutant plants show some compensatory increase in photosynthesis rate, which, however, is not enough to reach the level of the source ability as in the wild type since the number of seeds per plant is significantly decreased. The possibility of using this mutation in buckwheat breeding depends on the accumulation of modifiers that increase either leaf size or photosynthesis rate. The reduced number of flowers of the dfs mutation is compensated by an increase in flower fertility, and the number of seeds per plant does not change compared to the wild type. It explains the absence of differences between the dfs and wild type in terms of the photosynthesis rate. This experiment did not reveal any problems for using the dfc mutation in breeding. In general, the results of the work support the photosynthesis rate in buckwheat is regulated based on the source-sink ratio.