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020 _a968-6923-93-4
040 _aMX-TxCIM
072 0 _aF30
072 0 _aF60
082 0 4 _a633.153
100 1 _aSouza Machado, V.
_uDeveloping Drought- and Low N-Tolerant Maize. Proceedings of a Symposium; El Batan, Tex. (Mexico); 25- 29 Mar 1996
110 2 _aCentro Internacional de Mejoramiento de Maiz y Trigo (CIMMYT), Mexico DF (Mexico)
245 0 0 _aTriazole priming of maize seed to enhance drought tolerance during field establishment
260 _aMexico, DF (Mexico)
340 _aPrinted
520 _aLowland tropical maize environments are often characterized by unreliable rainfall distribution at planting time. Triazoles are plant growth regulators which moderate the effects of drought and high temperatures. We evaluated the triazole 'Paclobutrazol' as a seed primer on two maize cultivars in 1994 and on five maize cultivars in 1995 infield trials conducted at Tlaltizapan, Morelos and at Cocula, Guerrero, and in greenhouse studies at the University of Guelph. In 1994, seeds of hybrids 'P 3288' and 'NK TB 8101 ' were primed with Paclobutrazol 50 alone and in combination with Ancymidol 25 and grown under severe and moderate drought stress in the dry winter season. Compared with the non-primed check at Tlaltizapan, the triazole treatments delayed seedling emergence by 2.4-3.2 days, reduced plant height by 4%, delayed anthesis by 1.4-2.0 days and reduced grain yield by 11-17% across both drought treatments. At Cocula results were similar, though yield differences were non-significant due to a high coefficient of variation. In 1995, five cultivars ('CML8 x CML9', 'CML19 x CML27', 'La Posta Sequia C3', 'SIWA' and 'SIBA') (the last there from ClMMYT's drought breeding program), were seed treated with Paclobutrazol 80 imbibed, Paclobutrazol 20 seed coated, and in combination. The two field trials at Tlaltizapan involved a seedling survival trial with a gradation in levels of irrigation during the establishment phase and a mid-season drought stress trial. The seed coated treatment showed no significant response in either trial; the imbibing treatment reduced surviving seedling counts by 15-21% under severe water stress, slowed the rate of emergence, and resulted in non-significant reductions in biomass and grain yield. In greenhouse experiments at Guelph on the same genotypes and seed treatments, the Paclobutrazol imbibing treatment delayed emergence and reduced seedling height and fresh weight by 30% and 25% respectively, and gave inconclusive results under heat and drought stress. No differences were noted between the seed coated treatment and the check. We conclude that Paclobutrazol cannot be recommended at this stage as an imbibed seed treatment for tropical field maize.
546 _aEnglish
591 _a9801|AGRIS 9702|anterior|R97-98PROCE|FINAL9798
593 _aJose Juan Caballero
595 _aCPC
650 1 0 _aBreeding methods
650 1 0 _aDrought resistance
650 1 0 _91081
_aDrought stress
650 1 0 _aLowland
650 1 0 _aTropical zones
653 0 _aCIMMYT
650 1 0 _91314
_aZea mays
650 1 0 _91203
_aPlant breeding
700 1 _aAguilar-Mariscal, I.,
700 1 _aEdmeades, G.O.,
700 1 _aEdmeades, G.O.|Banziger, M.|Mickelson, H.R.|Peña-Valdivia, C.B.
700 1 _9800
_aAli, A.
_gSocioeconomics Program
942 _cPRO
999 _c3706