000			03581nab a22003497a 4500
001			G90451
003			MX-TxCIM
005			20230904175345.0
008			211105s2008 xxk|||p|op||| 00| 0 eng d
022			_a0021-8596
022			_a1469-5146 (Online)
024	8		_ahttps://doi.org/10.1017/S0021859608007818
040			_aMX-TxCIM
041			_aeng
090			_aCIS-5290
100	1		_aMonneveux, P. _920326
245	1	0	_aFuture progress in drought tolerance in maize needs new secondary traits and cross combinations
260			_aUnited Kingdom : _bCambridge University Press, _c2008.
340			_aComputer File|Printed
500			_aPeer review
520			_aThe use of secondary traits such as number of ears per plant, grains per ear, the interval from anthesis to silking, leaf senescence and leaf rolling, together with management of water stress and recurrent selection, have permitted a considerable increase in drought tolerance in the CIMMYT maize source germplasm populations Drought Tolerant Population (DTP) and La Posta Sequía (LPS). Inbred lines were extracted from DTP C9 and LPS C7 cycles and then used for generating single and three-ways hybrids. These were evaluated under normal irrigation and managed drought conditions. A weak, and in some cases no longer significant, correlation was found between grain yield and the traits initially used for selection. Most prominently, the relationship between anthesis-silking interval and grain yield became much weaker in these hybrids. Conversely, significant negative correlations were found between tassel dry weight and grain yield. Three-way hybrids involving two DTP lines yielded more than those involving one only, indicating the feasibility of gene pyramiding for drought tolerance. Overall, the results suggested that the relationship between grain yield and secondary traits has been modified due to continuous selection in the LPS and DTP populations. Some long-established secondary traits have become less important, while others have become more relevant. Mean grain weight, previously not used within a drought selection index, was strongly correlated with yield in the present study. The importance of traits related to the availability in C products for the development of ears and grains are discussed. The results indicate that the traits of source organs contribute marginally to drought tolerance; variation of leaf or root traits seems to be less important than variation in tassel parameters for increasing drought tolerance. For ensuring further progress in drought tolerance in maize, the solution might reside in the manipulation of sink organs. It is therefore suggested that selection for even greater number of ears, bigger grains and smaller tassels may help to increase grain yield under water limited environments in the near future. A short discussion on the optimal choice of parental lines for developing hybrids with maximum expression of drought tolerance concludes the paper.
546			_aText in English
650		7	_2AGROVOC _91173 _aMaize
650		7	_2AGROVOC _91082 _aDrought tolerance
650		7	_2AGROVOC _91008 _aAgronomic characters
650		7	_2AGROVOC _91155 _aInbred lines
700	1		_aSánchez Cano, C. _98515 _gGenetic Resources Program _81273525
700	1		_aTiessen, A. _97660
773	0		_tThe Journal of Agricultural Science _n635189 _gv. 146, no. 3, p. 287-300 _wG444500 _x0021-8596 _dUnited Kingdom : Cambridge University Press, 2008.
856	4		_yAccess only for CIMMYT Staff _uhttps://hdl.handle.net/20.500.12665/920
942			_cJA _2ddc _n0
999			_c27012 _d27012