Sweet Endosperm Research Articles

Diversity in Mohachao Narel, a Sweet Endosperm Coconut (Cocos nucifera L.) Population from Maharashtra, India

‘Mohachao Narel’, a coconut variant characterized by sweet and soft kernel with less fibre content, has been reported from Guhaghar taluk of Ratnagiri district of Maharashtra State in India. Farmers of the area get a premium price for sweet endosperm nuts and the sweet kernel is mainly consumed directly. A total of 28 mother palms possessing nuts with sweet kernel have been identified in these areas. The number of nuts with sweet endosperm per bunch varies from 10 to 77 percent in these 28 palms. In this study, 12 palm characters including vegetative as well as reproductive characters, 14 fruit characters and 14 SSR loci, distributed uniformly throughout the coconut genome, were used to assess the genetic diversity of these palms. Palms exhibited 18 and 33 % coefficient of variation in vegetative and reproductive characters respectively. In the case of vegetative characters, highest variation was detected in plant height followed by number of leaf scars per meter. Among the reproductive characters, number of female flowers per bunch possessed highest amount of variation followed by number of nuts per bunch. Among the 14 fruit characters studied, high variation was observed in the weight of embryo, husk weight, copra weight and oil content. The 14 SSR loci detected a total of 35 alleles with an average of 2.5 alleles per primer. All the primers were 100 % polymorphic. The analysis microsatellite revealed that palms of sweet kernel type had only 45 % similarity among them indicating the existence of a high level of genetic diversity between the palms. The results can pave the way for devising strategies for conservation and management of the sweet kernel coconut population and their use in future breeding programmes.

Efeito da heterose na qualidade de sementes de milho doce

Este trabalho teve por objetivo avaliar a qualidade fisiológica das sementes de genótipos selecionados de milho doce e sua relação com a heterose. Foram utilizados 14 genótipos de milho doce desenvolvidos pela Universidade Estadual do Norte Fluminense Darcy Ribeiro. Os genótipos foram multiplicados no município de Campos dos Goytacazes por meio de polinização controlada para assegurar a pureza genética. A qualidade fisiológica foi avaliada por meio do teste de germinação e dos seguintes testes de vigor: primeira contagem de germinação, classificação de plântulas e emergência em areia. Pelos resultados é possível concluir que as sementes de endosperma doce foram menos vigorosas que as sementes de endosperma comum. O emprego de genótipos parentais adaptados à região de plantio proporcionou melhor vigor às sementes de endosperma doce, quando comparado ao uso de parentais não adaptados. Para todas as características avaliadas de germinação e vigor observou-se heterose nas sementes híbridas em relação aos seus parentais. O desenvolvimento de híbridos pode ser uma excelente alternativa para a obtenção de sementes de milho doce vigorosas e de qualidade fisiológica superior.

Utilização de cobertura comestível na conservação pós-colheita de minimilho minimamente processado

Baby-corns were obtained from maize cultivars Vivi, simple hybrid of sweet endosperm in experimental phase and AG 1051commercial double hybrid, common, were coated with cassava starch edible coverage, at 2 and 4%, and stored at 5 oC. A control treatment, without coating, was used under the same conditions. Physicochemical analyses were conducted every three days for nine days; and daily analyses of mass loss were conducted from the third to the twelfth day. It was observed a variation in acidity, in pH, and in the total soluble solids contents of the samples during storage. There was no influence by the cassava starch coverage on the acidity and on the pH of the baby-corns obtained from cultivar Vivi at the end of storage; however, the acidity of cultivar AG 1051 increased. In general, it can be said that the coating process using cassava starch was effective in preserving the mass loss of baby-corn in cold storage of 5 oC. The performance of the experimental cultivar Vivi was similar to that of the commercial cultivar AG1051 for parameters such as mass loss (control and coverage at 4%) and acidity (coverage at 2 and 4%). On the other hand, it was better for SST parameter (coverage at 2 and 4%)

Development of one corn ear and verification the three laws of inheritance

A new corn was developed as a lab material to verify the three Laws of Inheritance on only one F2 ear with correct segregation ratios of kernel traits. In order to investigate the three Inheritance Laws simultaneously with one ear, the sweet endosperm (Sn1), kernel color (C1) and the glutinous endosperm (Wx) were chosen as the original phenotypes. Gene Sn1sn1 is located on chromosome four, genes C(1c1) and Wxwx are located on chromosome nine. After several generations of continuous self-pollination and test crossing, direct crossing and back crossing, with strict selections, the homozygous parents were obtained. With different combinations of homozygous parents, different hybrids were developed. The segregation ratios of each phenotype on the same F2 ear are compared to the theoretical segregation ratios according to the corn gene exchange and gamete types and quantities produced through meiosis. The results showed three ratios of 3:1, two ratios of 9:3:3:1, and one ratio of linkage and exchange, with all the chi-square values smaller than the permitted ones. This means that only one ear of this new hybrid corn can be used as a new teaching aid to examine and verify the three Laws of Inheritance.

EXPERIMENTS ON THE INHERITANCE OF NIACIN IN CORN (MAIZE)

In an earlier publication the writers (12) showed that the niacin concentration of dent corn behaved as a so-called quantitative character in inheritance, being determined by many genes of small individual effects. They also showed that niacin concentration could be modified rapidly by selection and saw no reason why hybrids with niacin concentrations as high as 50 micrograms/gram could not be developed. It was noted further that a second mode of inheritance had been reported (1, 9). In this, the starchy, Su, gene was dominant for lower niacin concentration over its su al?ele, just as it is dominant for starchy vs. sweet endosperm. We suggested that the influence of the Su su al?eles on niacin concentration was a secondary or pleiotropic one. There also was a suggestion (inconclusive) that the al?eles differentiating starchy and waxy (Wxwx) might operate similarly. Since our paper was written, workers at the Ohio Experiment Station have reported on niacin concentration in dent corn. Their earlier results (7) are open to some question because their material was open pollinated. Pollination accordingly could have been a differentiating influence, rather than environment as they concluded. Their later research was with handpollinated material. From this (4), they stressed the hereditary influence on niacin concentration, and suggested that it might be increased by breeding. Gorfinkel (5) also has reported practically complete dominance of the Su gene for lower niacin, and Cameron and Teas (3) have found the sugary types as conditioned at both the su and the du loci to be higher in niacin than the starchy types. Leng et al. (8) report the niacin concentration of sugary, waxy and dent kernels from segregating ears. Dent and waxy are not mutually exclusive, and neither are sugary and waxy. Their sugary class included the double recessive suwx kernels; whether or not their dent included waxy as well as starchy cannot be told. Correlations reported indicate a multiple effect of the su gene on both niacin concentration and carbohydrate formation, a pleiotropic action as postulated by Richey and Dawson (12). Leng et al. (8) also state that unpublished data indicate no close relation between kernel size and niacin concentration, in agreement with the conclusion previously reported by Richey and Dawson (12).