Relationship between fruiting efficiency and grain weight in durum wheat

• Published in: Field crops research 2015-06, Vol.177, p.109-116
• Main Authors: Ferrante, Ariel, Savin, Roxana, Slafer, Gustavo A.
• Format: Article
• Language: English
• Subjects: Grain number; Triticum durum; Yield; Yield components
• ISSN: 0378-4290; 1872-6852
• DOI: 10.1016/j.fcr.2015.03.009

•We studied differences in grain weight between two durum wheat cultivars with contrasting fruiting efficiencies.•Two alternative models, implying or not competition in floret growth, were proposed for the negative relationship.•Grain weight was consistently lower in the cultivar with higher fruiting efficiency, but the difference did not seem constitutive.•Increasing fruiting efficiency would have concomitantly increased the proportion of grains of smaller potential size rather than reducing grain weight constitutively.•Higher fruiting efficiency may therefore be relevant to further raise yield potential in wheat through increasing grain number. Future increases in grain number may be achieved through improving fruiting efficiency (FE; grains set per unit spike dry weight at anthesis). In recent experiments it was found a negative relationship between the average weight of the grains and FE. The objective of this paper was to determine whether this negative relationship was constitutive (i.e. the increased FE caused all grains to be smaller) or resulted from the increased proportion of grains of smaller potential size. Four experiments, involving 8 different environmental conditions, were carried out during two consecutive growing seasons (2008–2009 and 2009–2010) in which two durum wheat cultivars contrasting in FE and average grain weight were compared. In these conditions we determined FE and carried out a comprehensive study analysing in detail the weights of each individual grain along each of the spikelets. Averaging all experimental conditions, there was a negative relationship between average grain weight (GW) and fruiting efficiency (FE). Donduro with low FE produced in average heavier grains than Vitron. However, when considering individual grains there were, in general, no differences in GW. Therefore, the negative relationship between average grain weight and FE would not be constitutive, and would mostly represent the increase in the proportion of distal grains within the spikelets or of grains from apical spikelets as a consequence of an increased FE, reducing the average size of the grain but mostly unaffecting the size of particular grains. This provides further and stronger support to the idea of using FE as a criterion to further raise yield potential in wheat breeding programmes.