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Ovule dichotomy per locule of the trilocular pistil in cassava, Manihot esculenta: a useful abnormality for increased seed production?
Author(s) -
Ogburia M. N.,
Adachi T.,
Yabuya T.
Publication year - 2000
Publication title -
plant breeding
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.583
H-Index - 71
eISSN - 1439-0523
pISSN - 0179-9541
DOI - 10.1046/j.1439-0523.2000.00447.x
Subject(s) - ovule , biology , locule , gynoecium , hybrid , megaspore , botany , embryo rescue , cultivar , ovary , stamen , genetics , pollen , interspecific hybridization
Histologically, the cassava pistil is trilocular with a single ovule in each locule producing a maximum of three seeds in nature. Heat stress (35°/45°C, night/day temperatures), as a physical treatment was attempted to induce useful reproductive and vegetative traits in 10 F 1 hybrids derived from ‘OMR 36‐41’and ‘OMR 36‐42’crosses, and two Asian cassava cultivars,‘Rayong 60’and ‘Rayong 1′, under greenhouse and field conditions. Cytoembryological examination of the repro‐ ductive organs revealed morpho‐structural features of normal pistil in all clones except ‘Rayong 1’which exhibited reproductive variations under greenhouse culture. Genetically, an important variation was ovule dichotomy per locule of the trilocular pistil so that each pistil contained six instead of the usual three ovules and lacked any outer integument. These ovules possessed functional embryo sacs with varying nuclear number. A pair of the dichotomous ovules possessed two embryo sacs of apparent different megaspore mother cells. Vegetatively, F 1 hybrids were dwarf (0.50m) in their phenotype and flowered 1 month earlier than the 1.5‐2.0m tall cultivars under greenhouse conditions.