PRODUCTION OF DOUBLED HAPLOIDS IN TRITICALE (X TRITICOSECALE WITTM) BY MEANS OF CROSSES WITH MAIZE (ZEA-MAYS L) USING PICLORAM AND DICAMBA

The aim of the present study of triticale x maize crosses nias to find an appropriate growth regulator treatment to improve the yield of tri ticale haploids and the subsequent production of doubled haploids. The growth effect in unpollinated ovaries of triticale was examined after treatment with 1000 mg/l indole-3-acetic acid (IAA) or 100 mg/l solut ions of the following auxin analogues: 2,4-dichlorophenoxyacetic acid (2,4-D), 3,6-dichloro-o-anisic acid (dicamba), 4-chloro-o-tolyloxyacet ic acid (MCPA), phenylacetic acid (PAA), 4-amino-3,5,6-trichloropicoli nic acid (picloram) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T), r espectively. Dicamba stimulated growth of the ovaries significantly mo re than picloram and both stimulated more growth than the other growth regulators rested. Neither dicamba nor picloram induced embryo develo pment in unpollinated pistils. Dicamba and picloram solutions, at conc entrations of 25, 50, 75 and 100 mg/l, were subsequently applied to pi stils of triticale pollinated with maize. On average, between 17.1 and 21.5 embryos/100 florets were excised after treatment with 75 or 100 mg/l solutions of picloram or dicamba bur the concentrations of 20 and 50 mg were less effective. The frequencies of excised embryos did not differ between genotypes. Seventy-six green haploids were obtained fr om 100 embryos rescued in vitro on the 190-2 and modified B5 media, th e first medium being superior. The plants were subjected to colchicine treatment at the 3-4 tiller stage. Out of 68 plants brought to maturi ty, 25 exhibited fertile sectors. Ln comparison with previous studies, picloram and dicamba significantly improved the efficiency of the tri ticale x maize crossing. The low dependence on the mother germplasm ma kes triticale x maize crossing an efficient alternative to the androge netic methods of doubled haploid production in triticale.