Abstract
Enhancing the yield potential and stability of small-grain cereals, such as wheat (Triticum sp.), rice (Oryza sativa), and barley (Hordeum vulgare), is a priority for global food security. Over the last several decades, plant breeders have increased grain yield mainly by increasing the number of grains produced in each inflorescence. This trait is determined by the number of spikelets per spike and the number of fertile florets per spikelet. Recent genetic and genomic advances in cereal grass species have identified the molecular determinants of grain number and facilitated the exchange of information across genera. In this review, we focus on the genetic basis of inflorescence architecture in Triticeae crops, highlighting recent insights that have helped to improve grain yield by, for example, reducing the preprogrammed abortion of floral organs. The accumulating information on inflorescence development can be harnessed to enhance grain yield by comparative trait reconstruction and rational design to boost the yield potential of grain crops.
Highlights
This review focuses on genes that are responsible for inflorescence development and contribute to final grain number (GN) in Triticeae crops
Meristem identity genes during initial reproductive stages are well described in maize and rice and are among the most important genetic factors determining GN of panicle-type inflorescences (Tanaka et al, 2013; Kyozuka et al, 2014; Zhang & Yuan, 2014; Whipple, 2017; Bommert & Whipple, 2018)
Loss of function of the FLOWERING LOCUS T (FT)-B1 homoeolog increases the spikelet and tiller number when grown at lower temperatures (Dixon et al, 2018a). These findings support a pleiotropic function of FT beyond flowering, and further investigations might open up a new avenue towards improving inflorescence form
Summary
Complex inflorescence architectures and species-specific forms (Kellogg et al, 2013) that resulted from adaptation and artificial selection throughout evolution and domestication. During the transition to the reproductive stage, the vegetative shoot apical meristem (SAM) is transformed into an inflorescence meristem (IM), which produces branch meristems (BMs) in rice, sorghum (Sorghum bicolor), and maize (Tanaka et al, 2013). The BM produces a spikelet meristem (SM), and each spikelet generates one floret. Final spikelet number is determined by controlling the indeterminate BM phase in rice, sorghum, and maize (Table 1; Koppolu & Schnurbusch, 2019). The spikelets of wheat are indeterminate and usually produce eight to 12 florets (Fig. 2c); of these, three to. The oat (Avena sativa) inflorescence (panicle) combines characteristics of rice and wheat inflorescences, with branches, a terminal spikelet, and indeterminate spikelets (Bonnett, 1966). An improved understanding of the trajectory of changing inflorescence architecture could facilitate future crop improvement
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
