Cucurbit Genetics Cooperative Report 19:53-56 (article 19) 1996
Jaagrati Jain and T.A. More
Division of Vegetable Crops, Indian Agricultural Research Institute, New Delhi-110012, India
Introduction. Some of the major diseases of muskmelon (e.g., cucumber green mottle mosaicism, powdery mildew and Fusarium wilt) have been reported in Delhi and surrounding areas, thereby highlighting the need to develop multiple disease resistant varieties. This can be achieved by adopting conventional breeding methods of interspecific hybridization, and overcoming interspecific incompatibility (5). In the present study, a step towards somatic hybridization/protoplast fusion involved identifying and selecting donor lies/sources of resistance with suitable genetic marker(s), outlining their regeneration potential and determining their vegetative and fruit characteristics.
Materials and Methods. Seven marker lines of melon were selected as donor lines based on the information on genetic markers in the cucumis melo L. gene list (3,5). Two cultivated varieties of melon, Pusa Sharbati (PS) and Pusa Madhuras (PM), and a good performing developing line M4 were selected as recipient lines (5).
Since the availability of somatic hybrids is based upon the regeneration potential of the two parent cells/lines, it became necessary to outline the regeneration potential of donor and recipient lines in the present research work.
Regeneration response of the seven donor and three recipient line was studied in 1990 and 1991, on a prestandardized callus formation medium of MS + 0.5 mg/l benzyl adenine (MB) and a differentiation medium of MS+1.0 mg/IAA and 5.0 mg/l kinetin (MIK) (1). Two of the recipient lines, PM and M4, had already been reported in 1991 and 1992 to possess high regeneration potential governed by dominant G (2).
Characterization for vegetative and fruit characters involved percentage germinability under controlled conditions in a net house on a soil mixture of FYM:sand:soil in the ratio of 1:1:1 (v/v/v). Donor and recipient lines were screened for Fusarium wilt and cucumber green mottle mosaicism (CGMMV) under field conditions at various stages of development up to fruit harvest, and for significant vegetative character and fruit characters (Tables 2 and 3) during the cropping period from February to the middle of June in 1992, 1993 and 1994.
Results. Seven marker lines were chosen based on their genetic resistance to powdery mildew and Fusarium wilt. EC-327435 and EC-327434 are known to possess genes for powdery mildew resistance (Pm-1 and PM-2, and Pm-4 andPM-5, respectively). EC-327437 and EC-327440 possess the Fusarium wilt resistance genes Fom-1 and Fom-3, respectively, and EC-327438 and EC-38439 possess the vegetative characters dissected leaf (dl) and green leaves (gl) respectively (Table 1).
Based on regeneration studies, it was found that except for EC-327434 no other donor line differentiated on a standardized medium (Table 1). Among the recipient lines, PM and M4 possess high regenerability; PS was found to be nearly non-regenerative and therefore cannot be involved in somatic hybridization studies.
Germination of EC-327434 and EC-327440 was 100 percent, while that of EC-327435 was 83% (Table 2). EC-327434 was found to be sensitive to CGMMV and did not reach the flowering stage, hence there was no fruit formation. However, EC-327435 and EC-327440 reached the fruit harvest stage, and hence were characterized for vegetative and fruit characters along with the recipient lines.
Tables 3 and 4 describe the vegetative and fruit characteristics of the donor and recipient accessions. Fruits of EC-327435 were round to oval in shape with orange-yellow pulp, and weighed approx. 350 g with a T.S.S. of approx. 4%. Fruits of EC-327440 were flat-round to oblong in shape with pale green pulp, weighed approx, 840 g and had a T.S.S. of 5.3%. Among the recipient lines, fruits of PM were small sized with a high T.S.S. of 8.6%, fruits of M4 were large sized with a T.S.S. of 6.7, and fruits of PS (which was non-regenerative in culture) were small at 575 g and had a T.S.S. of 6.5%/
Discussion. EC-327434 can be utilized as a donor lines for marker genes Pm-4 and Pm-5 with the indigenous cultigens (PM and M4) which have been identified for a genetic marker G for high regeneration potential (2). Further work is required in outlining the feasibility of interlineal hybridization between identified and donor selected lines with the isogenic lines of available indigenous cvs., in addition to somatic hybridization.
Table 1. Regeneration response of marker donor lines and recipient cultivars of Cucumis melo L.
Regeneration Response (5) |
||||||
Marker lines or cultivars |
Genetics |
Explant |
Callus formation |
Callus differentiation into shoot buds |
Callus differentiation into roots |
No change |
Donor lines |
||||||
| EC-327434 | PI 124112 | Cot. leaves | 9.1 | 72.7 | 18.2 | 0 |
| (PM-4. PM-5) | Epicotyl | 81.8 | 9.1 | 0 | 9.1 | |
| EC-327435 | PMR-5 | Cot. leaves | – | – | – | 100 |
| (PM-1, PM-2) | Epicotyl | – | – | – | 100 | |
| EC-327436 | Va435 (n&v) | Cot. leaves | – | – | – | 100 |
| Epicotyl | – | – | – | 100 | ||
| EC-327437 | Charentais | Cot. leaves | – | – | – | 100 |
| (Fom-1) | Epicotyl | – | – | – | 100 | |
| EC-327438 | Marker (dl) | Cot. leaves | – | – | – | 100 |
| Epicotyl | – | – | – | 100 | ||
| EC-327439 | Marker (gl) | Cot. leaves | – | – | – | 100 |
| Epicotyl | – | – | – | 100 | ||
| EC-327440 | Perlita FR | Cot. leaves | – | – | – | |
| (Fom-3) | Epicotyl | – | – | – | 100 | |
| 100 | ||||||
Recipient lines |
||||||
| Pusa Madhuras | aaG_ | Cot. leaves | 83.3+28.9 | 16.7+2.9 | 0.0 | 0.0 |
| Epicotyl | 33.3+7.2 | 66.7+7.2 | 0.0 | 0.0 | ||
| Pusa Sharbati | aaG_ | Cot. leaves | 0.0 | 1.7+2,9 | 0.0 | 98.3+2.9 |
| Epicotyl | 0.0 | 0.0 | 0.0 | 100 | ||
| Developing M4 | A_G_ | Cot leaves | 56.1+20.3 | 30.5+6.8 | 0.0 | 13.4+4.2 |
| Epicotyl | 75.2+12.3 | 23.8+10.8 | 0.0 | 1.0+0.7 | ||
Table 2. Seed germinability and sensitivity to Fusarium oxysporum f.sp.melonis and cucumber green mottle mosaic virus (CGMMV) in marker donor lines and recipient cultivars of melon.
| Accession/cy. | Germination (%) | Sensitivity to Fusarium wilt | Sensitivity to CGMMV | Fruits with seeds harvested |
| EC-327434 | 100.0+0.0 | ++y | NASw | No |
| EC-327435 | 83.3+14.4 | –x | – | Yes |
| EC-327436 | 41.7+14.4 | ++ | NAS | No |
| EC-327437 | 83.3+14.4 | ++ | NAS | No |
| EC-327438 | 4.0+1.5 | ++ | NAS | No |
| EC-327439 | 41.7+14.4 | ++ | NAS | No |
| EC-327440 | 100.0+0.0 | – | – | Yes |
| Pusa Madhurasz | 100.0+0.0 | – | – | Yes |
| Pusa Sharbati | 37.5+4.2 | – | – | Yes |
| M4 | 83.3+0.8 | – | – | Yes |
z Control
y Not sensitive
x 100% sensitive
w NAS=not available for scoring
Table 3. Descriptive vegetative and fruit characters of marker donor lines and recipient cultivars of melon.
Accessions/cvs. |
Vegetative characters |
Size and shape of the fruit |
Color of the skin |
No. of vein tracts |
Flesh color |
| EC-327434 | Dark green leaves, leaf margin inundated, somewhat rough leaf surface | –Fruits not available — | |||
| EC-327435 | Small, closely placed green leaves with smoothlinear margin, hairy petiole | Small size, round to oval shape | Yellowish green, wrinkled skin | 10 | Orangish yellow |
| EEC-327440 | Large leaves with rough surface and hairy petiole | Flat round to oblong in shape, medium sized fruits | Greenish gray, rough rectum, pattern of the skin | 10 | Pale green |
| M4 (developing line) | Small, closely placed yellowish green leaves with smoothleaf surface | Round, large sized | Greenish yellow, smooth skin | 10 | Greenish yellow |
| Pusa Sharbati | Small, fast gowing plant | Flat round, small sized | Orange green with rough and reticulate pattern of skin | 10 | Dark orange |
| Pusa Madhuras | Fast growing, yellowish green leaves with smooth serratedleaf margin, tendrils present | Flat round small skin with dark green vein tracts | Yellowish green, smooth | 10 | Orangish yellow |
Table 4. Fruits characteristics of donor marker lines and recipient cultivars of melon.
Accessions/ccs. |
Fruits harvested |
Fruit weight (g) |
Flesh thickness (cm) |
Cavity (cm) |
Fresh seeds weight (g) |
T.S.S. (&) |
| EC-327434 | – | – | – | – | – | – |
| EC-327435 | + | 350.0+95.4 | 2.2+0.4 | 5.4+0.0 | 60.0+33.2 | 4.0+0.0 |
| EC-327440 | + | 840.0+84.9 | 2.4+0.2 | 5.6+0.2 | 115.0+7.1 | 5.3+0.4 |
| M4 | + | 1331.5+143.8 | 3.0+0.3 | 7.2+1.7 | 230.6+84.0 | 6.7+1.4 |
| Pusa Sharbati | + | 575.0+35.4 | 3.5+0.7 | 5.3+0.4 | 56.0+7.1 | 6.5+0.7 |
| Pusa Madhuras | + | 588.1+50.4 | 2.4+0.5 | 7.3+0.2 | 142.3+35.0 | 8.6+0.2 |
Acknowledgment: The senior author (JJ) would like to thank Dr. T.A. Moore, at present Head and Professor of Department of Horticulture, College of Agriculture, Kolhapur, Maharashtra, India, for his association as Project Leader up to May 1993.
Literature Cited
- Jain, J. and T.A. More, 1992. In vitro regeneration in Cucumis melo cv. Pusa Madhuras. Cucurbit Genetics Coop. Rept. 15:62-64.
- Jain, J. and T.A. More. 1993. Genotypic control of regeneration potential in Cucumis melo. Cucurbit Genetics Coop. Rept. 16:53-54.
- Jain, J. and T.A. More. 1994. Preliminary screening of indigenous cultivars and a few known marker lines of Cucumis melo for Fusarium wilt and CGMMV resistance. Cucurbit Genetics Coop. Rept. 17:69-71.
- Jain, J. and T.A. More. 1995. Regeneration response of a few genetic marker lines and commercial cultivars of Cucumis melo L. cucurbit Genetics Coop. Rept. 18:48-49.
- Jain, J. and T.A. More. 1991. Contribution in: Research achievements in muskmelon. In: H.S. Gill, T.A. More, N. Singh and A.S. Kataria, eds. Vegetable Research-1 ‘resume’ (1956-90). Ahnkur Publishers, New Delhi. pp. 17-2k.
- Pitrat, Michael. 1990. Gene list of Cucumis melo L. Cucurbit Genetics Coop. Rept. 13:58-68.