Genotypic Control of Regeneration Potential in Cucumis melo

admin

Cucurbit Genetics Cooperative Report 16:53-54 (article 19) 1993

J. Jain and T.A. More
Division of Vegetable Crops, Indian Agricultural Research Institute, New Delhi – 110012, INDIA

Present study was undertaken to outline the genotypic control of regeneration potential in C. melo. Three sex forms viz. andromonoecious (Pusa Madhuras), gynoecious (GM-5D, GM-7 and GM-6E-7) and monoecious M4 were utilized in regeneration studies to find out the genotypic control of regeneration potential of different sex forms.

Materials and Methods. In vitro regeneration studies were carried out in Pusa Madhuras, GM-5D, GM-6C-4, GM-7, GM-6E-7, and M4. Both epicotyl and cotyledonary explants were used. Pre-standardized de-differentiation medium of MS + 0.5 mg/1 (MB) and differentiation medium of MS + 1.0 mg/1 IAA and 5.0 mg/1 Kinetin (MIK) were used following the usual procedure of regeneration (1). Callus obtained on MB medium was transferred to MIK medium after 2-3 weeks, for differentiation of shoot buds.

Results. Among the various sex forms of C. melo, andromonoecious sex form (Pusa Madhuras) has been found to be highly responsive to regeneraiton on pre-standardized de-differentiation and differentiation medium (Table 1). The four gynoecious forms showed no response to callus formation on MB medium. Similarly neither any direct regeneration nor callus induced regeneraiton was observed on MIK medium. In monoecious sex form (M4) cotyledonary leaf explants were found to be equally responsive to differentiation medium than explants of Pusa Madhuras. In epicotyl explants of M4, 23.82( + 10.80) per cent callus induced regeneration was observed in comparison to 66.66 (+ 7.21) per cent callus induced regeneration observed in Pusa Madhuras epicotyl explants.

Discussion. Various sex forms of Cucumis melo differ in twow genes A & G. The andromonoecious form (Pusa Madhuras) is homozygous recessive for a and homozygous dominant for G whereas the monoecious form M4 has a genotype of A-G (3, 4, 5). The gynoecious sex form is designated as A-g g plus modifiers at g locus (5). The high regeneration potential observed in Pusa Madhuras (1) and M4 (2) may be governed by dominant G. Dominant A has a repressing effect on regeneration.

Table 1. Regeneration response of various sex forms of C. melo¹

Various sex forms

Explant

Explants forming callus (%)

Explants with shoots (%)

No response (%)
Andromonoecious Epicot. 33.33 + 7.21 66.66 + 7.21 0
(Pusa Madhuras) Cot. leaf 83.33 + 28.86 16.66 + 8.86 0
Monoecious (M4 ) Epicot. 75.18 + 12.30 23.82 + 10.80 0.98 + 0.67
Cot leaf 56.10 + 20.30 30.49 + 6.76 13.39 + 4.20
Gynoecious
GM-5D Epico. 0 0 100
Cot. leaf 0 0 100
GM-6C-4 Epicot. 0 0 100
Cot. leaf 0 0 100
GM-7 Epicot. 0 0 100
Cot. leaf 0 0 100
GM-6E-7 Epicot. 0 0 100
Cot. leaf 0 0 100

¹Epicotyl and cotyledonary explants were incubated on de-differentiation medium (MS + 0.5 mg/1 BA) for 2-3 weeks before transfer to shoot bud differentiation medium (MS + 1.0 mg/1 IAA and 5.0 mg/1 Kinetin.

Literature Cited

  1. Jain, J. and T.A. More. 1992. In vitro regeneration in Cucumis melo cv. Pusa Madhuras. Cucurbit Genetics Cooperative Report No. 15, pp.62-64.
  2. Jain, J. and T.A. More. 1992. Regeneration potential of various accessions of muskmelon, Cucumis melo L. Fifth Eucarpia Cucurbitaceae Symposium, held at Poland.
  3. Rosa, J.T. 1928. The inheritance of flower types in Cucumis and Citrullus. Hilgardia 3:233.
  4. Vegetable Breeding. 1988. Vol. I, pp. 3-11. Ed., Dr. Kalloo. CRC Press Inc., Florida.
  5. Vegetable Research – A resume (1956-90). 1991. pp 17-25. Eds., H.S. Gill, T.A. re, N. Singh, and A. S. Kataria. Ankur Publishers; New Delhi.