Effect of seed desicction and storage on seed vigour and germination in four species of indigenous fruit trees
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Date
2002
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Publisher
Sokoine University of Agriculture
Abstract
A study was conducted for Cordyla africana Lour, C. densiflora Milne.Redh.,
Strychnos cocculoides Baker and 5. spinosa Lam., in the laboratory, to investigate desiccation tolerance and storage conditions that will maintain high seed vigour and
germination. Three experiments were conducted: Initial, desiccation sensitivity and
storage trials. For initial and desiccation trial, a Randomized Complete Block
Design with four replications was used. For storage trial, a 5 x 4 x 3 factorial
experiment with four replications was conducted.actor one was moisture contents
at five levels: C. africana (50, 38, 25, 13 and 8%); C. densiflora (54, 41, 27, 14 and
10%); S. cocculoides (43, 32, 22, 11 and 5%) and S. spinosa (41, 31, 21, 10 and
5%). Factor two was storage temperature at four levels, -20, 4, 16 and 25° C and
factor three was packaging materials at three levels, polyethylene bags cotton cloth
bags and aluminum foil bags. Germination test was conducted after every 2, 4, 8
and 20 weeks. Assessment were done for, daily germination percent, final
germination percent, radicle elongation, germination value and germination energy
percent. Seed of C. africana and C. densiflora were found to be sensitive to
desiccation, seed vigour and viability were substantially reduced after desiccation
from 50 to 13% and from 54 to 14% respectively. For S. cocczdoides and S. spinosa
seed viability and vigour were not sensitive to desiccation. Storage conditions
significantly influenced seed viability and vigour after two weeks of storage. Seeds
of C. africana and C. densiflora maintained high final cumulative germination of 90
and 95% and higher radicle elongation of 19 and 42 mm respectively, for seeds
stored with their initial moisture content at 16°C in cotton cloth bags. Germination value and germination energy followed the same trend. For 5. cocculoides and S.
spinosa seeds were not significantly affected by storage. It is concluded that. Seeds
of C. africana and C. densiflora are recalcitrant and those of 5. cocculoides and .S'.
spinosa are intermediate. It is recommended that seeds of C. africana and C.
densiflora should be stored with moisture content between 25 and 50% and 27 and
54% in cotton cloth bag at 16° C respectively, for period no exceeding eight weeks
Seeds of 5. cocculoides and 5. spinosa can be stored for up to 20 weeks in
polyethylene bags, with moisture content between 5 and 40% at temperatures of >
4°C but not exceeding 25°C. Further study should be conducted to determine rates
of cell membrane disruption during desiccation.
Description
Dissertation
Keywords
Seed storage, Africana seed, Densiflora seed, Fruits trees