Role of In Situ Seed Desiccation in the Control of Seed Viability of Cassava ( Manihot esculenta crantz) Hybrids TMS 95/0379 and TMS 98/0505
Year: 2018
Type: article
Abstract: Seeds from mature cassava (Manihot esculenta Crantz) fruits exhibit low seed viability (one viable seed/fruit), possess hard seed coat and germinate poorly. Since the formation of hard seed coat is associated with the desiccation/last stage of seed development, we wondered whether cassava seed viability was related to seed moisture content. Therefore, the objectives of this study were: 1) to quantify the viability of seeds of two cassava varieties (TMS 98/0505 and TMS 95/0379) collected prior to the formation of hard coat, 2) to determine the relationship between seed viability and seed moisture content, and 3) to determine the suitability of top soil, moist filter paper, fine sand as growth medium for germinating young cassava seeds. Stem cuttings of the two varieties were cultivated on the field for seed production. Fruits were sampled two times at 6 and 10 weeks after first anthesis. Seeds extracted from the fruits had either thin, colorless seed coats or moderately thickened, light brownish seed coat. The seeds were subjected to flotation and tetrazolium chloride (TCL) tests for viability, evaluated for moisture content and subjected for germination in three growth media (top soil, fine sand and moist filter paper). Seed viability increased significantly (p<0.01) from approx. one seed/fruit (0.50) at 6 WAA to approx. all seeds per fruit (0.92) at 10 WAA in TMS 98/0505. In TMS 95/0379, seed viability was 0 at 6 WAA. Flotation test was found to overestimate seed viability at 6 WAA in both varieties. In TMS 98/0505, moisture content per seed significantly (p<0.01) declined from 0.80 g/seed to 0.50 g/seed as collection date was delayed from 6 WAA to 10 WAA. Moisture content was generally higher in TMS 95/0379 than TMS 98/0505. There was no interaction effect. The relationship between seed moisture content and seed viability was significant (p<0.001), and strongly linear (R²=0.89) and negative. There was no record of germination in the three-growth media which suggest that greater than one viable seed/fruit can be obtained before the formation of hard seed coat in TMS 98/0505 but methods that can germinate them needs to be developed.
Authors: Godson D. Nnedue, Elsie I. Hamadina
Language: English
Subfield: Plant Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: diamond
OpenAlex ID: W2802629606