Understanding the composition and contents of carotenoids in various soybean seed accessions is important for their nutritional assessment.  This study investigated the variability in the concentrations of carotenoids and chlorophylls and revealed their associations with other nutritional quality traits in a genetically diverse set of Chinese soybean accessions comprised of cultivars and landraces.  Genotype, planting year, accession type, seed cotyledon color, and ecoregion of origin significantly influenced the accumulation of carotenoids and chlorophylls.  The mean total carotenoid content was in the range of 8.15–14.72 µg g^–1 across the ecoregions.  The total carotenoid content was 1.2-fold higher in the landraces than in the cultivars.  Soybeans with green cotyledons had higher contents of carotenoids and chlorophylls than those with yellow cotyledons.  Remarkably, lutein was the most abundant carotenoid in all the germplasms, ranging from 1.35–37.44 µg g^–1.  Carotenoids and chlorophylls showed significant correlations with other quality traits, which will help to set breeding strategies for enhancing soybean carotenoids without affecting the other components.  Collectively, our results demonstrate that carotenoids are adequately accumulated in soybean seeds, however, they are strongly influenced by genetic factors, accession type, and germplasm origin.  We identified novel germplasms with the highest total carotenoid contents across the various ecoregions of China that could serve as the genetic materials for soybean carotenoid breeding programs, and thereby as the raw materials for food sectors, pharmaceuticals, and the cosmetic industry.

To optimize the spatial distribution of cotton bolls and to increase the yield, the relationship between yield components and boll spatial distribution was investigated among different Bt (Bacillus thuringensis) cotton varieties.  A five-year field experiment was conducted to reveal the reasons for the differences in lint yield and fiber quality across three Bt cotton varieties with different yield formations from 2013 to 2017.  The lint yield of Jiman 169 (the average yield from 2013–2017 was 42.2 g/plant) was the highest, i.e., 16.3 and 36.9% higher than Lumianyan 21 (L21) and Daizimian 99B (99B), respectively.  And the differences in boll weight among the three cultivars were similar to the lint yield, while the others yield components were not.  So the increase in lint yield was mainly attributed to the enlargement in boll weight.  However, the change in fiber quality was inconsistent with the lint yield, and the quality of L21 was significantly better than that of Jimian 169 (J169) and 99B, which was caused by the diversity of boll spatial distribution.  Compared with 99B, the loose-type J169 had the highest number of large bolls in inner positions; the tight-type L21 had a few large bolls and the highest number of lower and middle bolls.  And approximately 80.72% of the lint yield was concentrated on the inner nodes in Jiman 169, compared with 77.44% of L21 and 66.73% of 99B during the five-year experiment.  Although lint yield was significantly affected by the interannual changes, the lint yield of J169 was the highest and the most stable, as well as its yield components.  These observations demonstrated the increase in lint yield was due to the increase in boll weight, and the large bolls and high fiber quality were attributed to the optimal distribution of bolls within the canopies.