Regeneration Response of a Few Genetic Marker Lines and Commercial Cultivars of Cucumis melo L.

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Cucurbit Genetics Cooperative Report 18:48-49 (article 23) 1995

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

Introduction: A few known marker lines (5) were obtained from Montfavet, France, in order to use the marker genes in somatic hybridization studies. These studies were initiated to investigate the possibility of overcoming interspecific incompatibility (2) in order to incorporate disease resistance genes into cultivars (6). Thus, it became necessary to characterize the marker lines for their ability to regenerate under the conditions conducive for regeneration in cv. Pusa Madhuras (PM) (3) and a developing line M4 (4).

Materials and Methods: Regeneration response of epicotyl and cotyledonary explants of cultivars and seven known genetic marker lines was studied on a pre-standardized callus formation medium of MS+0.5 mg/l benzyladenine (MB) and a differentiation medium of MS+1.0 mg/l1 IAA and 5.0 mg/l kinetin (MIK) (3,4). The various marker lines were classified based on their regeneration response in 1993.

Results: No marker line except EC-327434 [PI 124112, (Pm-4, Pm-5)] was found to be responsive to regeneration (Table 1). Cotyledonary leaves explant callus of EC-327434 was found to be responsive to shoot buds differentiation on MIK medium. The epicotyl explant callus could not differentiate into shoot buds. Success of shoot buds differentiation from callus was obtained in only 9.1 per cent of the explants; 81.8 per cent of explants remained in the undifferentiated callus stage. EC-327434, known for carrying powdery mildew resistant genes Pm-4 and Pm-5, however, could not grow beyond the vegetative stage in the field and was found to be sensitive to Fusarium wilt (5). Among the cvs Arka Jeet and M4 , cotyledonary leaves explant callus exhibited differentiation in the range of 63.6 per cent and 30.5 6.8 per cent, respectively. Cv. Pusa Madhuras epicotyl explant callus was more regenerative than cotyledonary explant callus. The shoot buds differentiation was observed in 66.7 7.2 per cent of calli.

Discussion A known genetic marker line EC-327434, being maintained as a genetic stock at Montfavet, France, can be utilized in somatic hybridization studies for marker genes, Pm-4 and Pm-5 with the available indigenous cv. PM, a developing line M4 and with other commercial cultivars (1) after outlining their regeneration response. Cv. PM and M4 have already been identified for a genetic marker G for high regeneration potential (4) but with incomplete expressivity in resistance for CGMMV and Fusarium wilt (5, 6). Marker lines EC-327435, known for genetic marker Pm-1 and Pm-2, and EC-327440, known for genetic marker Fom-3 , cannot be utilized in somatic hybridization studies as they do not differentiate into callus. However, they were found to reach the seeded fruit stage (5) in the field. Cv. Arka Jeet is not suitable for cultivation in Delhi (5).

Table 1. Regeneration response of a few known genetic marker lines and cultivars of Cucumis melo L.

Callus differentiation into

Accessions/Cvs

zExplant

y Callus proliferation
Shoot buds
Roots

No change
Accessions:
EC-327434 x Cot. lvs 9.1 72.7 18.2 0.0
w epicot 81.8 9.1 0.0 9.1
EC-327435 Cot. lvs. 0.0 0.0 0.0 100
epicot 0.0 0.0 0.0 100
EC-327436 Cot. lvs. 0.0 0.0 0.0 100
epicot 0.0 0.0 0.0 100
EC-327437 Cot. lvs. 0.0 0.0 0.0 100
epicot 0.0 0.0 0.0 100
EC-327438 Cot. lvs. 0.0 0.0 0.0 100
epicot 0.0 0.0 0.0 100
EC-327439 Cot. lvs. 0.0 0.0 0.0 100
epicot 0.0 0.0 0.0 100
EC-327440 Cot. lvs. 0.0 0.0 0.0 100
epicot 0.0 0.0 0.0 100
Earlibush Cot. lvs. 0.0 0.0 0.0 100

Crenshaw

 epicot. 0.0 0.0 0.0 100
Indigenous Cvs.
Arka Jeet Cot. lvs. 27.3 63.6 0.0 9.1
epicot 27.3 9.1 63.6 0.0
Pusa Cot. lvs. 0.0 1.7 + 2.9 0.0 98.3 + 2.9

Sharbati

 epicot. 0.0 0.0 0.0 100
Pusa Cot. lvs. 8303 + 28.9 16.7 + 2.6 0.0 0.0

Madhuras

 epicot. 33.3 + 7.2 66.7 + 7.2 0.0 0.0
M4 Cot. lvs. 56.1 + 20.3 30.5 + 6.8 0.0 13.4 + 4.2
epicot. 75.2 + 12.3 23.8 + 10.8 0.0 1.0 + 0.7

zCallus formation on MS+0.5 mg/l benzyladenine.
yCallus proliferation and differentiation on MS + lmg/l IAA + 5mg/l kinetin.
xCotyledonary leaves
wEpicotyl

Literature Cited:

  1. Bordas,m M., V. Moreno and L.A. Roig. 1991. Organogenic and Embryogenic potential of several commercial linesof Cucumis melo L. Cucurbit Genet. Coop. Rept. 14:71-73.
  2. Chatterjee, M. and T.A. More. 1991. Interspecific hybridisation in Cucumis spp. Cucurbit Genet. Coop. Rept. 14:69-70.
  3. Jain, J. and T.A. More. 1992. In vitro regeneration in cucumis melo Cv. Pusa Madhuras. Cucurbit Genet Coop. Rept. 16:53-54.
  4. Jain, J. and T.A. More. 1993. Genotypic control of regeneration potential in Cucumis melo, Cucurbit Genet Coop. Rept. 16:53-54.
  5. Jain, J. and T.A. More. 1994. Preliminary screening of indigenous cultivars and a few iknown marker lines of Cucumis melo for Fusarium wilt and CGMMV resistance. Cucurbit Genet. Coop. Rept. 17:69-71.
  6. More, T.A., Varma, V.S., Seshadri, R.G. Somkumar and L. Rajamony. 1993. Breeding and development of cucumber green mottle mosaic virus (CGMMV) resistant lines in melon (Cucumis melo L.). Cucurbit Genet. Coop Rept. 16:44-46.