Staining of heterochromatin bands and the determination of rye chromosomes in triticale (wheat × rye hybrid)

Summary Fifteen lines of triticale were studied using the C-banding staining method. A typical, complete chromosomal complement was found in 11 lines, while the remaining lines demonstrated some variations. A slight modification in the technique is discussed.Supported in part by CSRS/USDA Grant No. 801-15-03A.     

Comparisons of Mayan forest management, restoration, and conservation

Numerous communities associated with at least five distinct ethnic Mayan groups in southern Mexico and Central America continue to rely upon forested areas as integral components of their agricultural systems. They carefully manage these areas so that forests provide food, raw materials, and animals. Management practices include removing and planting of woody and herbaceous species, apiculture, and seed harvest. Mayan agroforestry systems in geographically and ecologically distinct areas of Mesoamerica were evaluated to better understand traditional agroforestry system components and how indigenous Mayan agroforestry could be a part of regional forest conservation and restoration. Systems were within Mexican land grant areas (ejidos) or on contested land. Although these systems rely upon different woody species and management techniques, common among them are: (1) the use of multi-stage and successional pathways with forest as a part of the larger system, (2) species that are believed by traditional ecological knowledge (TEK) to accelerate forest regeneration - more than 30 tree species are recognized and managed as potential facilitators of forest regeneration and (3) direct human consumption of forest products at all stages of regeneration.     

Association analysis of fibre traits in Gossypium arboreum accessions

Advances in the use of diploid Asiatic species in cotton breeding require an understanding of the relatedness and ancestry of diploid cotton accessions, and identification of simple sequence repeat (SSR) markers associated with agronomically important phenotypic traits, for example, fibre quality. Fifty‐six Gossypium arboreum germplasm accessions introduced from nine regions of Africa, Asia and Europe were evaluated for eight fibre characters (lint percentage, lint colour, elongation, micronaire, strength, 50% span length, 2.5% span length and maturity%) and genotyped with 98 SSR markers. When viewed across all accessions most of the SSR markers were polymorphic. Population structure analysis identified six main clusters for the accessions which corresponded to different geographic regions, indicating agreement between genetic and predefined populations. The general linear model method was used to disclose marker–trait associations. Marker–trait associations were investigated by fitting single marker regression models for phenotypic traits on marker band intensities with correction for population structure. This paper illustrates the potential of association mapping in diploid cotton, because existing phenotypic data, a modest number of SSR markers, and a pioneering statistical analysis, identified interesting associations.