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Accueil du site → Master → Kenya → 2008 → A study of Rhodes grass (Chloris gayana Kunth) seed quality and variations during marketing in Uasin Gishu District and their effect on stand establishment

University of Eastern Africa, Baraton, Kenya (2008)

A study of Rhodes grass (Chloris gayana Kunth) seed quality and variations during marketing in Uasin Gishu District and their effect on stand establishment

Motanya, Winston Moenga

Titre : A study of Rhodes grass (Chloris gayana Kunth) seed quality and variations during marketing in Uasin Gishu District and their effect on stand establishment

Auteur : Motanya, Winston Moenga

Université de soutenance : University of Eastern Africa, Baraton, Kenya

Grade : Master of Philosophy (M Phil) 2008

Résumé
Variations between and within pasture grass seed lots of Rhodes grass (Chloris gayana - Kunth cv Boma) may compromise the stated seed quality standards. The significant effects of variations in viability and vigour between and within seed lots value makes the Pure Germinating Seed (PGS) a superficial statement and not an accurate guarantee of the planting quality and expected stand establishment. Growers of Rhodes grass rarely get good and rapid germination from all purchased seed lots. The emergence of seedlings is rarely uniform and it takes a long time before adequate canopy cover is obtained and ideal biomass for grazing achieved. This predisposes livestock farmers to pasture shortages. This study was aimed at determining the variations in seed quality attributes between and within Rhodes grass seed lots at marketing and finding out how these variations affect stand establishment. The study was carried out at the Kenya Plant Health Inspectorate Services (KEPHIS), Lanet, and at The Department of Seed, Crop and Horticultural Sciences, Moi University, Chepkoilel Campus, Uasin Gishu District, Kenya in October 2004 to November 2005. Laboratory tests for viability and vigour were carried out on four certified seed lots of Rhodes grass (cv Boma) purchased from seed stockists in Eldoret town, Kenya. Laboratory tests for purity, viability and vigour and Field experiments for field emergence and vigour were arranged in a Randomized Complete Block Design (RCBD). The daily growth rates of single seedlings during the heterotrophic stage were used to determine the variation between seeds in the laboratory. The collected data was subjected to Analysis of Variance (ANOVA) and the means separated by the Least Significant Difference (L.S.D.) using SPSS version 12.0. Coefficients of variation, mean-median difference and standard deviations were used to show variation between seeds. Significant differences in germination (P < 0.01), mean time to germination (P < 0.001), purity (P < 0.01), electrical conductivity (P < 0.01) and caryopsis count (P < 0.001) were found between seed lots. Field emergence was much lower than laboratory germination in all seed lots. Increase in within-lot variations correlated with decrease in bulk quality. The results show that there are differences in viability and variations in the vigour of Rhodes seeds available to farmers in Uasin Gishu which may affect the germination, vigour and stand establishment of sown seed. They also show that Potassium nitrate reduces the germination of Rhodes grass seed. The results support the incorporation of caryopsis count on pure seed fractions as an additional check to guarantee purity. Vigour tests give more accurate assessments on germination uniformity and of the planting quality of pasture seed.

Sujets : Rhodes grass ; Chloris gayana ; Seeds ; Marketing ; Uasin Gishu District ; Grasses ;

Présentation (Research Kenya) -> http://www.researchkenya.or.ke/thes...)-seed-quality-and-variations-during-marketing-in-uasin-gishu-district-and-their-effect-on-stand-establishment

Page publiée le 5 décembre 2016, mise à jour le 7 mai 2019