000			01099nab a22003737a 4500
999			_c12651 _d12651
001			G40526
003			MX-TxCIM
005			20200602163926.0
008			121211s1993 ne |||p op||| | eneng d
022			_a0378-4290
024	8		_ahttps://doi.org/10.1016/0378-4290(93)90065-U
040			_aMX-TxCIM
041	0		_aeng
043			_aNL
072		0	_aF30
072		0	_aH50 F01
090			_aCIS-2773
100	1		_aBolaños, J. _95538
245	1	0	_aEight cycles of selection for drought tolerance in lowland tropical maize. 1. Responses in grain yield biomass, and radiation utilization
260			_aAmsterdam (Netherlands) : _bElsevier, _c1993.
340			_aPrinted
500			_aPeer review
500			_aPeer-review: Yes - Open Access: Yes|http://science.thomsonreuters.com/cgi-bin/jrnlst/jlresults.cgi?PC=MASTER&ISSN=0378-4290
520			_aDrought is a major source of grain yield instability in maize (Zea mays L.) grown in the lowland tropics, and use of cultivars with improved drought tolerance may be the only affordable option for many small-scale farmers. Eight cycles of full-sib recurrent selection were carried out in the population ‘Tuxpeño Sequía’ during the rain-free winter season at Tlaltizapán, Mexico, under controlled moisture stress timed to coincide either with flowering or grain-filling. Selection was based on an index comprising grain yield and physiological and morphological traits with presumed adaptive value under drought. The objectives of this study were to evaluate direct and correlated responses to selection in grain yield and its components, total biomass, and radiation-use efficiency (RUE). Cycles 0, 2, 4, 6 and 8 of Tuxpeño Sequía, and a check cultivar representing the results of six cycles of selection based primarily on multilocation testing, were evaluated under three moisture regimes at Tlaltizapán during two consecutive winter seasons. Grain yield (GY) increased at 108 kg ha−1 cycle−1 across 12 yield environments ranging in yield potential from 1 to 8 Mg ha−1, with no significant interaction between gains and moisture environments. Yield gains resulted from an increase of 0.03 ears per plant (EPP) cycle−1 under drought, and small but significant increases in EPP, kernel number per ear and kernel weight in well-watered environments. Selection had no effect on biomass production, so yield increases were due to a gain in harvest index (HI) of 0.0058 to 0.0067 cycle−1 in either wet or dry environments. Seasonal readiation-use efficiency averaged 1.48 g MJ−1 PAR under well-watered conditions, a value lower than expected for maize. Although selection slightly reduced radiation interception and slightly increased RUE during the pre-anthesis phase, both changes were relatively unimportant. The regression of GY on biomass (B) (GY = - 1.85 + 0.47B; R 2 = 0.94 " ) predicted zero GY at biomass yields of less than 4 Mg ha−1. The check entry showed only limited progress in drought tolerance, EPP, HI, and GY. These results suggest that drought stress, when managed to coincide with flowering, can be an effective selection environment for increasing HI, yield stability, and GY of lowland tropical maize across a wide range of moisture environments.
546			_aText in English
591			_aR93ANALY|Elsevier|MP|3
595			_aCSC
650		7	_91897 _aBiomass _2AGROVOC
650		7	_aDrought resistance _2AGROVOC _93104
650		7	_aLowland _2AGROVOC _913684
650		7	_aSelection _2AGROVOC _94749
650		7	_aTropical zones _2AGROVOC _94259
650		7	_aYield factors _2AGROVOC _96137
650		7	_91314 _aZea mays _2AGROVOC
700	1		_aEdmeades, G.O. _95520
773	0		_tField Crops Research _n624858 _gv. 31, no. 3-4, p. 233-252 _dAmsterdam (Netherlands) : Elsevier, 1993. _wu444314 _x0378-4290
942			_cJA _2ddc _n0