Enhanced production of doubled haploid lines from parthenogenetic Iranian melon plants obtained of irradiated pollen (Cucumis melo L.)

Abstract:Haploid and doubled haploid plants are valuable materials for plant breeding purposes such as resistance to many fungal and viral diseases that affect this crop. We produced 48 parthenogenetic melon plantlets via pollination with ?-irradiated pollen witch 550 Gray of dose cloned them by nodal cuttings, and tested the effects of in vitro and in vivo doubling treatment on survival, ploidy and fruit recovery. Chromosome number was counted in root tip cells from in vitro haploid plants .The most effective procedure for explants recovery was in vitro treatment of shoot tip explants with 500 mg/l colchicine for 12 h in standard medium and plant regeneration from nodal explants treated with 500 mg/L colchicine for 12 h was increased from 33 to 76% by removing apical dominant one week before colchicine treatments. The growth regulators medium (5 µM IAA; 5 µM BA; 1 µM ABA; 30 µM AgNO3) callus production was caused as a result of delayed regeneration. The most doubling occured in 24h treatment from soot tip explant. This treatment gave 49% survived of explants and 20% conservation to diploidy. In in vivo treatments, 2000 mg/l colchicine for 24h treatment was the effectiveness than other dose with 18% doubling rate.