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Starch gel electrophoresis was carried out to investigate inheritance of aconitase (ACO), shikimate dehydrogenase (SKDH), and phosphoglucose isomerase (PGI) in guayule (Parthenium argentatum Gray). Self-incompatibility of diploid guayule (2n = 36), prevented production of F2 generations. A series of crosses was made for segregation analysis. The enzyme ACO showed two zones of activity—one monomorphic and the other polymorphic, representing one locus with two alleles. SKDH was found to be coded by two loci with three alleles at each locus. Four zones of activity were found for PGI. PGI-1, the fastest zone, was poorly resolved and appeared variable. Segregation data indicated that PGI-2 is monogenic and controlled by five codominant alleles. Poor resolution of PGI-4 made it impossible to determine whether PGI-3 was the product of a separate locus or resulted from intergenic cross dimerization between PGI-2 and PGI-4. The dimeric characteristic of PGI-2 and the monomeric structure of SKDH and ACO-1 in guayule agreed with the protein structures previously reported for these enzymes in other plant species. The isozyme variation of this investigation maybe used in a breeding program to identify sexual and maternal type progenies of facultative apomictic guayule plants at the early seedling stage.
Abstract
Sixteen genotypes of mung bean (Vigna radiata (L.) Wilczek var. radiata) were subjected to 18 treatment combinations (environments) resulting from 3 levels of N, 3 planting densities, and 2 planting times. Measurements were made on yield and its components: pods per plant, seeds per pod, and seed weight. Cluster analysis was used to provide an index of similarity of the genotypes for each character. Genetic similarity of the genotypes, as indicated by a “one-trait-at-a-time” analysis, is reflected in their phenetic similarity in an 18 dimensional space corresponding to the 18 environments. No relationship between geographic distribution and genetic diversity was obtained for all characters. Information on the diversity of the components of yield would be useful in choosing parents that yield superior progenies. Pods per plant was the most important component followed by seeds per pod, and seed weight. Selection of parents for the component characters, with regard to high performance and genetic diversity, are expected to follow the same order.