Stories from the Greenhouse—A Brief on Cotton Seed Germination

Seed germination is the basis for the proliferation of sexual-reproducing plants, efficient crop production, and a successful crop improvement research program. Cotton (Gossypium spp.), the subject of this review, can be often sensitive to germination conditions. The hardness of the cotton seed coat, storage, extreme temperatures, and dormancy are some of the factors that can influence cotton seed germination. Research programs conducting studies on exotic and wild cotton species are especially affected by those hurdles. Here, we briefly review the challenges of cotton seed germination and some of the approaches our cotton breeding program explored throughout the years

Diallel Crosses of Cotton (<i>Gossypium hirsutum</i> L.) from Burkina Faso and Texas A&M AgriLife Research—1-Analysis of Agronomic Traits to Improve Elite Varieties from Burkina Faso

Cotton breeding progress stagnation, changing production conditions, and continued high fiber quality demands are challenging the cotton industry in Burkina Faso. The F1 populations developed by half diallel crosses between germplasm from Texas A&M AgriLife Research and Burkina Faso were evaluated for several agronomic traits. The aim was to identify the most promising parents and hybrids for further varietal improvement. Three AgriLife parents helped improve the most important targeted traits. Parent 15-3-416 reduced days to 50% flowering (−3.14 days) and shortened plant height (−22.25 cm) in hybrids while 16-2-216FQ improved their fiber percentage (+2.68%). Hybrids with Burkina Faso elite cultivar E32 as male parent and the three best AgriLife parents as the females showed good specific combining ability (SCA). FK37 × 15-10-610-7 and FK64 × 15-10-610-7 showed heterosis for earliness by reducing, respectively, days to 50% flowering (−4.27 days) or days to 50% boll opening (−3.95 days) below parent means. E32 × 16-2-216FQ and FK64 × 16-2-216FQ increased fiber percentage by +1.75% and +2.06%, respectively. FK64 × 15-3-416 increased seed index (SI) (+0.62 g) and fiber percentage (+1.19%), while maintaining other traits at the parents’ average levels. E32 × 15-3-416 showed the most heterosis for desired improvements, reducing days to 50% flowering (−4) and increasing the number of bolls/vegetative branch (+3.05), number of bolls/fruiting branch (+6.38), number of bolls/plant (+13.49), boll weight (+1.53 g), SI (+0.40 g), and fiber percentage (+1.18%). Inter-program crosses show the potential to enhance genetic diversity in Burkina Faso’s breeding program. Subsequent selection methods must be carefully applied considering the Burkina Faso breeding objectives for future cultivars

Responses of Upland Cotton (Gossypium hirsutum L.) Lines to Irrigated and Rainfed Conditions of Texas High Plains

Understanding drought stress responses and the identification of phenotypic traits associated with drought are key factors in breeding for sustainable cotton production in limited irrigation water of semi-arid environments. The objective of this study was to evaluate the responses of upland cotton lines to rainfed and irrigated conditions. We compared selected agronomic traits over time, final yield and fiber quality of cotton lines grown in irrigated and rainfed trials. Under rainfed conditions, the average number of squares per plant sharply declined during weeks 10 to 14 while the average number of bolls per plant significantly reduced during weeks 13 to 15 after planting. Therefore, weeks 10 to 14 and weeks 13 to 15 are critical plant growth stages to differentiate among upland cotton lines for square and boll set, respectively, under drought stress. Variation in square and boll set during this stage may translate into variable lint percent, lint yield and fiber properties under water-limited conditions. Lint yield and fiber quality were markedly affected under rainfed conditions in all cotton lines tested. Despite significantly reduced lint yield in rainfed trials, some cotton lines including 11-21-703S, 06-46-153P, CS 50, L23, FM 989 and DP 491 performed relatively well under stress compared to other cotton lines. The results also reveal that cotton lines show variable responses for fiber properties under irrigated and rainfed trials. Breeding line 12-8-103S produced long, uniform and strong fibers under both irrigated and rainfed conditions. The significant variation observed among cotton genotypes for agronomic characteristics, yield and fiber quality under rainfed conditions indicate potential to breed cotton for improved drought tolerance

Functional screening in human HSPCs identifies optimized protein-based enhancers of Homology Directed Repair

Homology Directed Repair (HDR) enables precise genome editing, but the implementation of HDR-based therapies is hindered by limited efficiency in comparison to methods that exploit alternative DNA repair routes, such as Non-Homologous End Joining (NHEJ). In this study, we develop a functional, pooled screening platform to identify protein-based reagents that improve HDR in human hematopoietic stem and progenitor cells (HSPCs). We leverage this screening platform to explore sequence diversity at the binding interface of the NHEJ inhibitor i53 and its target, 53BP1, identifying optimized variants that enable new intermolecular bonds and robustly increase HDR. We show that these variants specifically reduce insertion-deletion outcomes without increasing off-target editing, synergize with a DNAPK inhibitor molecule, and can be applied at manufacturing scale to increase the fraction of cells bearing repaired alleles. This screening platform can enable the discovery of future gene editing reagents that improve HDR outcomes