糯玉米是主要的鲜食玉米类型之一，waxy基因突变导致了玉米籽粒的糯性。中国糯玉米地方品种丰富，云南及其周边地区被认为是糯玉米的起源中心和遗传多样性中心。已知中国糯玉米waxy等位基因包括wx-D7、wx-D10、wx-Cin4、wx-124、wx-Reina和wx-xuanwei。这些等位基因的突变位点都发生在waxy基因的编码区，而调控区引起waxy基因的突变在玉米中却鲜有报道。本研究以405份云南糯玉米地方品种为材料，通过分子标记检测，鉴定waxy基因上游3.5Kb调控区的大片段插入和缺失。研究发现三类不同的waxy等位基因：wx-PIF/Harbinger、wx-hAT和wx-Elote2。三类等位基因分别属于304bp的PIF/Harbinger家族 MITE类转座子的插入、560bp的hAT家族MITE类转座子的插入和6560bp的LTR-like转座子的插入。此外研究中完成了云南70%以上的糯玉米地方品种waxy等位基因的鉴定，可为糯玉米地方品种的利用提供基础

Founder parents have contributed significantly to the improvement of wheat breeding and production.  In order to investigate the genetic characteristics of founder parents and widely planted cultivars, Mazhamai (M), Biyumai (B) and six sibling lines (BM1–6) derived from the cross M×B were phenotyped for eight yield-related traits over multiple years and locations and genotyped using the the wheat 90K single nucleotide polymorphism (SNP) assay.  BM4 has been used as a founder parent, and BM1 has been widely planted, whereas BM2, 3, 5, and 6 have not been used extensively for breeding or planting in China.  Phenotypic comparisons revealed that BM4 and BM1 displayed a better overall performance than the other sibling lines.  BM1 showed higher thousand-grain weight than BM4, whereas BM4 exhibited lower coefficient of variation for most of the yield-related traits across different years and locations, indicating that BM4 was widely adaptable and more stable in different environments.  SNP analysis revealed that BM4 and BM1 inherited similar proportions of the M genome but are dissimilar to BM2, 3, 5, and 6.  Both BM1 and BM4 have specific alleles that differ from the other BM lines, and most of these alleles are concentrated in specific chromosomal regions that are found to associate with favorable QTLs, these SNPs and their surrounding regions may carry the genetic determinants important for the superior performance of the two lines.  But BM4 has more genetic diversity than BM1 with more specific alleles and pleiotropic regions, indicating that the genome of BM4 may be more complex than the other sibling lines and has more favorable gene resources.  Our results provide valuable information that can be used to select elite parents for wheat and self-pollinating crop breeding.

   Grain number per spike (GNPS) is a major factor in wheat yield breeding.  A new wheat germplasm Pubing 3504 shows superior features in spike traits.  To elucidate the genetic basis of spike and yield related traits in Pubing 3504, 282 F2:3 families were generated from the cross Pubing 3504×Jing 4839, and seven spike and yield related traits, including GNPS, spike length (SL), kernel number per spikelet (KPS), spikelet number per spike (SNS), thousand-grain weight (TGW), spike number per plant (SNP), and plant height (HT) were investigated.  Correlation analysis indicated significant positive correlations between GNPS and spike-related traits, including KPS, SNS, and SL, especially KPS.  A genetic map was constructed using 190 polymorphic simple sequence repeat (SSR), expressed sequence tag (EST)-SSR, and sequence-tagged-site (STS) markers.  For the seven traits measured, a total of 37 quantitative trait loci (QTLs) in a single-environment analysis and 25 QTLs in a joint-environment analysis were detected.  Additive effects of 70.3% (in a single environment) and 57.6% (in a joint environment) of the QTLs were positively contributed by Pubing 3504 alleles.  Five important genomic regions on chromosomes 1A, 4A, 4B, 2D, and 4D could be stably detected in different environments.  Among these regions, the marker interval Xmag834–Xbarc83 on the short arm of chromosome 1A was a novel important genomic region that included QTLs controlling GNPS, KPS, SNS, TGW, and SNP with stable environmental repeatability.  This genomic region can improve the spike trait and may play a key role in improving wheat yield in the future.  We deduced that this genomic region was vital to the high GNPS of Pubing 3504.

The wheat grain number per spike (GNPS) is a major yield-limiting factor in wheat-breeding programs. Germplasms with a high GNPS are therefore valuable for increasing wheat yield potential. To investigate the molecular characteristics of young spike development in large-spike wheat germplasms with high GNPS, we performed gene and protein expression profiling analysis with three high-GNPS wheat lines (Pubing 3228, Pubing 3504 and 4844-12) and one low-GNPS control variety (Fukuho). The phenotypic data for the spikes in two growth seasons showed that the GNPS of the three large-spike wheat lines were significantly higher than that of the Fukuho control line. The Affymetrix wheat chip and isobaric tags for relative and absolute quantitation-tandam mass spectrometry (iTRAQ-MS/MS) technology were employed for gene and protein expression profiling analyses of young spike development, respectively, at the floret primordia differentiation stage. A total of 598 differentially expressed transcripts (270 up-regulated and 328 down-regulated) and 280 proteins (122 up- regulated and 158 down-regulated) were identified in the three high-GNPS lines compared with the control line. We found that the expression of some floral development-related genes, including Wknox1b, the AP2 domain protein kinase and the transcription factor HUA2, were up-regulated in the high-GNPS lines. The expression of the SHEPHERD (SHD) gene was up-regulated at both the transcript and protein levels. Overall, these results suggest that multiple regulatory pathways, including the CLAVATA pathway and the meristem-maintaining KNOX protein pathway, take part in the development of the high-GNPS phenotype in our wheat germplasms.