Tiller angle (TA) strongly influences plant architecture and grain yield in cereals. However, the genetic basis of TA in wheat is largely unknown. We identified three TA-related quantitative trait loci (QTL). One of them was QTa.sau-2B-769, a major QTL localized on chromosome arm 2BL. QTa.sau-2B-769 was detected in seven environments, explaining 18.1%–51.1% of phenotypic variance. We developed a linked Kompetitive Allele-Specific Polymerase chain reaction (KASP) marker, KASP-AX-108792274, to further validate this locus in three additional populations in multiple environments. QTa.sau-2B-769 increased TA by up to 24.9% in these populations. There were significant and positive correlations between TA and flag leaf angle (FLANG). However, TA was not correlated with plant height or anthesis date, suggesting that expression of QTa.sau-2B-769 is independent of vernalization. TraesCS2B01G583800, a gene known to be involved in leaf angle regulation, was identified as the most likely candidate gene for QTa.sau-2B-769. These results enrich our understanding of the mechanisms regulating wheat TA at maturity and may support precise mapping and cloning of gene(s) underlying QTa.sau-2B-769.

Genomic DNA and cDNA sequences of an isoamylase gene were isolated and characterized from the rye genome. The full-lengths of the rye isoamylase gene are 7351 bp for genomic DNA and 2364 bp for cDNA. There are 18 exons and 17 introns in the genomic sequence, which shares a similar organization with homologous genes from Aegilops tauschii, maize, rice and Arabidopsis. Exon regions of rye and other plant isoamylase genes are more conserved than the introns. High sequence similarity (>95%) was observed in mature proteins of isoamylase genes originating from rye, Ae. tauschii, wheat and barley. The transcript profile revealed that rye isoamylase is mainly expressed in the seed endosperm with a maximum level at the middle developmental stage (15 DPA). A phylogenetic tree based on the deduced aa sequences of mature proteins from rye and other plant isoamylases indicated that rye isoamylase is more closely related to Ae. tauschii wDBE1 and wheat iso1. This is the first report on identification and characterization of the isoamylase gene from rye, making it possible to explore the roles of this enzyme for amylopectin development in rye and triticale.