ABSTRACT
Foxtail millet [Setaria italica (L.) P. Beauv.], as a rich source of folates, has been cultivated on arid infertile lands, for which N deficiency is one of the major issues. Growing environments might have a significant influence on cereal folate levels. However, little is known whether N deficiency modulates cereal folate levels. In order to obtain enriched folate foxtail millet production in nutrient-poor soil, we conducted a study investigating the content of folate derivatives of 29 diverse foxtail millet cultivars under two N regimes (0 and 150 kg N ha-1) for 2 years to explore folate potential grown under low N. The contents of total folate and most derivatives were reduced by N deficiency. The effect on total folate content caused by N was stronger than cultivar genotype did. Folate content of enriched folate cultivars was prone to be reduced by N deficiency. Structural equation models (SEMs) revealed that N fertilization had a positive indirect effect on grain folate content through influencing plant N and K accumulation. Collectively, the results indicate much more attention should be paid to N management when foxtail millet is cultivated in infertile soil, to improve foxtail millet folate contents.
ABSTRACT
Foxtail millet (Setaria italica) is a versatile grain and fodder crop grown in arid and semi-arid regions. It is an especially important crop for combating malnutrition in certain poverty-stricken areas of the world. Photoperiod sensitivity is a major constraint to the distribution and utilization of foxtail millet germplasm resources. Foxtail millet may be suitable as a model species for studying the photoperiod sensitivity of C4 crops. However, the genetic basis of the photoperiod response of foxtail millet remains poorly studied. To detect the genetic basis of photoperiod sensitivity-related traits, a recombinant inbred line (RIL) population consisting of 313 lines derived from a cross between the spring-sown cultivar "Longgu 3" and the summer-sown cultivar "Canggu 3" was established. The RIL population was genotyped using whole-genome re-sequencing and was phenotyped in four environments. A high-density genetic linkage map was constructed with an average distance between adjacent markers of 0.69 cM. A total of 21 quantitative trait loci (QTLs) were identified by composite interval mapping, and 116 candidate genes were predicted according to gene annotations and variations between parents, among which three genes were considered important candidate genes by the integration and overall consideration of the results from gene annotation, SNP and indel analysis, cis-element analysis, and the expression pattern of different genes in different varieties, which have different photoperiod sensitivities. A putative candidate gene, SiCOL5, was isolated based on QTL mapping analysis. The expression of SiCOL5 was sensitive to photoperiod and was regulated by biological rhythm-related genes. Function analysis suggested that SiCOL5 positively regulated flowering time. Yeast two-hybrid and bimolecular fluorescence complementation assays showed that SiCOL5 was capable of interacting with SiNF-YA1 in the nucleus.
ABSTRACT
Taking two winter wheat varieties Gaocheng 8901 and Yannong 21 with different end-use qualities as test objects, a field experiment was conducted in the experimental farm of Shandong Agricultural University from 2008 to 2010, aimed to study the effects of different planting density and spraying PP333 on the basal stem morphological characteristics, snapping-resistance, lodging-resistant index, and grain yield. Gaocheng 8901 had higher lodging-resistance but lower grain yield than Yannong 21. Comparing with low planting density (180 x 10(4) basic seedlings per hm2), high planting density (240 x 10(4) basic seedlings per hm2) decreased the culm snapping-resistance and lodging-resistant index of the two varieties, especially Yannong 21. Spraying PP333 decreased the plant height and the basal internodes length, increased the snapping-resistance and lodging-resistant index, strengthened the lodging-resistance, and improved the spike number and grain yield. Correlation analysis showed that the second internode length, percentage of basal internodes (1 + 2) length to total internode length, and apparent lodging ratio were significantly negatively correlated with culm lodging resistant index. Therefore, to adopt an appropriate planting density combined with spraying PP333 could improve the lodging-resistance of winter wheat and its grain yield, being an important high-yielding cultivation technique for wheat production in sub-humid zone.
