Problems and results of doubled haploid plant production in pepper (Capsicum annuum L) via anther and microspore culture

More than 500 pepper varieties, breeding lines and F-1 hybrids were investigated in anther culture. A decreasing androgenic response was obtained in wax-type, dark green blocky-type, tomato-shaped and Cayenne/chilli-type peppers (from 76 to 0 plants/100 cultured anthers). Although bell peppers generated a high and reproducible response, spice peppers proved to be less or non-responsive. An in vitro colchicine treatment was applied to the haploid regenerated plants for chromosome doubling with a 75% rediploidization rate. One responsive (Feherozon) and two poorly responsive (No. 40017 R-13 and No. 40017 RK-II) genotypes were selected for microspore culture experiments. Three basic culture media were used with different carbohydrate and growth regulator supplements. The highest frequency of microspore divisions was obtained on NLN-2-15 medium (modified Lichter, 1981 medium containing 2% saccharose, 0.5 mg/l NAA and 0.5 mg/l BA). Sporophytic divisions resulted in some multicellular pollens, but embryo development from these structures has not been obtained yet. Stigma co-culture, exine wall digestion and the colchicine effect on microspore divisions were investigated. Although neither the stigma co-culture nor the enzyme treatment could increase the cell division frequency, the positive effect of the drug (25 mg/l for 24 h) on the microspore development was clear.