000			03892nam a22004457a 4500
001			G80084
003			MX-TxCIM
005			20230704201319.0
008			121211s ||||f| 0 p|p||0|| |
020			_a970-648-120-6
040			_aMX-TxCIM
041			_aeng
072		0	_aE16
072		0	_aF01
090			_aCIS-4154
100	1		_9832 _aPixley, K.V. _gGenetic Resources Program _8INT1617
245	1	0	_aOpen-pollinated maize varieties : _ba backward step or valuable option for farmers?
260			_aNairobi (Kenya) : _bCIMMYT, _bKARI, _c2002.
300			_a8 pages
340			_aPrinted
520			_aMaize farmers require varieties appropriate to their anticipated level of investment in inputs and ,with high probability of producing an acceptable grain yield when challenged by common biotic and abiotic constraints. The objectives of this study were to quantify the relative genetic advantage of hybrids over OPVs under a range of growing conditions typical for farmers in southern and eastern Africa, both when first- or second-generation ("recycled") seed is used, and to investigate scenarios under which hybrids or OPVs are the more profitable option for farmers. In our first experiment, we found that four elite hybrids consistently produced about 18%. more grain yield than 10 improved elite OPVs when grown at 16 sites with mean yield between 1.8 and 7.3 t ha-l. We proceeded to examine the consequences of recycling or saving grain from hybrid or OPV maize crops for use as seed for subsequent crops. Trials at five sites in Zimbabwe compared planting of FI seed and F2 grain of 10 commercial hybrids, FI and F2 of 10 topcross hybrids (using an OPV as male for a single cross), and F2 and F3 of 10 OPVs. Use of the advanced generation grain instead of Fl (F2 in the case of OPVs) seed resulted in 32%. average yield loss for hybrids, 16% yield loss for topcrosses and 5% yield loss for OPVs. We used these results to conduct simple break-even yield analyses to identify scenarios where use of OPV rather than hybrid varieties might be economically advantageous. We concluded that in some farming systems, particularly where yield levels are low (e.g. below 1.5 t ha-l) and hybrid seed and fertilizer prices are high relative to price of grain, highest return to investment may result from use of improved OPV seed, which is cheaper than hybrid seed and can be recycled with little or no yield loss. The improved OPVs are particularly advantageous if the money saved by using OPV instead of hybrid seed is used to purchase additional inputs such as fertilizer, herbicide or hiring additional labor. Although use of OPV instead of hybrid seed is a backward step in terms of expected grain yield, improved OPVs represent an economical option for resource-poor maize farmers in marginal areas or when hybrid seed and fertilizer prices are high relative to price of grain.
536			_aGenetic Resources Program|Research and Partnership Program
546			_aText in English
591			_a0409|AGRIS 0401|AL-Maize Program
594			_aINT1888|INT1617
595			_aCSC
650	1	7	_aCrop yield _2AGROVOC _91066
650	1	7	_aEconomic analysis _2AGROVOC _91088
650	1	7	_aExperimentation _2AGROVOC _94432
650	1	7	_aFarmers _91654 _2AGROVOC
650	1	7	_aFertilizers _2AGROVOC _91111
650	1	7	_aGrowth _2AGROVOC _99439
650	1	7	_aMaize _2AGROVOC _91173
650	1	7	_aPollination _2AGROVOC _95187
650	1	7	_aVarieties _2AGROVOC _91303
650	1	7	_91151 _aHybrids _2AGROVOC
700	1		_aBanziger, M. _gResearch & Partnership Program _gExcellence in Breeding _8INT1888 _9834
773			_dNairobi (Kenya) : CIMMYT, KARI, 2004. _gp. 22-28 _tIntegrated Approaches to Higher Maize Productivity in the New Millennium; Proceedings of the Eastern and Southern Africa Regional Maize Conference, 7; Nairobi (Kenya); 5-11 Feb 2002 _wG79461 _z970-648-120-6
942			_cPRO _2ddc
999			_c7321 _d7321