Influence of Stage of Fruit Maturity, Chemicals and Growth Media on Germination, Growth and Vigour of Papaya Seedling
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Date
2016-06
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University of Agricultural Science, Dharwad
Abstract
A study to understand the genetics of fibre elongation was conducted at University of Agricultural Sciences Dharwad during kharif 2015-16. The SEM images of ovule at 2 DPA revealed that chalazal and middle parts of ovule are entirely covered with fibre initials whereas, extreme micropylar part of ovule is free from fibre initials in MCU5 (WT), Fuzzy-lintless (Fl) and Fuzzy-linted (FL) lines. The quantification of number of fibre initials on 2 DPA ovule surface (100 µm2 area) showed that almost no fibre initials (only 2) had emerged on the ovule surface of MCU5 (fl) mutant but markedly high number of fibre initials (118) were observed in MCU5 (WT) ovules. In diploid both Fuzzy-lintless (Fl) and Fuzzy-linted (FL) lines recorded fibre initials but fibre initials observed in case of Fuzzy-lintless line will not elongate to become lint. Therefore in the present study parents considered are linted (fibred) and lintless (fibreless) as supported by electron micrographic studies more suitable for understanding genetics of fibre elongation. The chi-square test in F2 indicated that lintless trait in diploid cotton and fuzzless-lintless trait in tetraploid cotton was governed by double recessive gene (15:1).
Ginning outturn recorded wide variability in tetraploid (0 to 43.90 %) and diploid (0 to 38.08 %) F2 population. In tetraploid F2 plants, lint coverage area increases towards micropylar end from chalazal end of the seed as ginning outturn increases. Number of fibres per seed varies from 0 to 2,333 in the plants had ginning outturn respectively in the range of 0 to 13.78 % this difference in number of elongating fibres per seed was the reason for wide variation observed in ginning outturn per cent. From these results, targeting the increase in number of elongating fibres per unit area to increase ginning outturn becomes important research component.