000			03769nab a22004697a 4500
001			G39842
003			MX-TxCIM
005			20231006175535.0
008			231006s1992 it |||p|op||| 00| 0 eng d
022			_a0025-6153
040			_aMX-TxCIM
041	0		_aeng
043			_aIT
072		0	_aF01
072		0	_aF30
090			_aCIS-1756
100	1		_aVasal, S.K. _95280
245	1	0	_aHeterotic patterns of ninety-two white tropical CIMMYT maize lines
260			_aBergamo (Italy) : _bIstituto Sperimentale per la Cerealicoltura, _c1992.
340			_aComputer File Printed
500			_aPeer-review: Yes - Open Access: Yes|http://science.thomsonreuters.com/cgi-bin/jrnlst/jlresults.cgi?PC=MASTER&ISSN=0025-6153
500			_aTables, references p. 270
500			_aPeer review
500			_aOpen Access
520			_aDevelopment of inbred-based populations which are heterotic to each other was considered one of the primary goals when CIMMYT started its hybrid maize program in 1985. The objectives of this study were to determine the combining ability and heterotic patterns of tropical maize (Zea mays L.) inbred lines developed at CIMMYT and to identify and form heterotic groups for the tropics. Ninety-two tropical late white inbred lines at S3-S6 levels of inbreeding derived. from nine CIMMYT populations and pools were crossed to four tester lines (two dent and two flint). The 368 line x tester combinations were divided into four sets, eachset comprising of crosses of 23 lines to the four testers and tested in multilocation trials during 1988 to 1990. Mean grain yield for the four sets ranged from 5.6 to 6.5 t/ha. General combining ability (GCA) and specific combining ability (SCA) estimates for grain yield were calculated using line x tester analysis. Twenty-one of the 34 lines from Population 21 had positive GCA estimates for yield. Of the nine lines tested from Population 43, seven showed positive GCA effects for yield. The four testers behaved differently for GCA effects in different sets except Tester 3 (Pop. 25) which showed positive GCA effects for yield in all the sets and in the combined data. SCA effects for yield were significant in each set. Several line x tester hybrid combinations yielded more than 7 t/ha. Generally, crosses of lines from Population 43 to Populations 32 or 25 had higher grain yields. Interpopulation crosses were usually superior to intrapopulation crosses. A few crosses within Population 21 and Population 25 gave yields comparable to some of the best interpopulation combinations. Based. on the testcross data, two tropical heterotic groups THG "A" and THG "B" were formed which will be useful for future hybrid development work at CIMMYT and national programs in the tropics. Several of the lines included in this study were announced as CIMMYT maize lines (CML) during 1991, and are available to both public and private breeders. Twelve of the 20 top-yielding crosses (five from each set) involved CML lines.
546			_aText in English
591			_aR92ANALY|MP|12541-R|3
650		7	_aCombining ability _92367 _2AGROVOC
650		7	_aGermplasm _2AGROVOC _91136
650		7	_aInbred lines _2AGROVOC _91155
650		7	_91211 _aPlant population _2AGROVOC
650		7	_aYield components _91312 _2AGROVOC
650		7	_91314 _aZea mays _2AGROVOC
700	1		_aSrinivasan, G. _96538
700	1		_aPandey, S., _91500
700	1		_aCordova, H. _95333
700	1		_aHan, G.C. _927600
700	1		_aGonzález Ceniceros, F. _9485
773	0		_tMaydica _n620726, 620991 _gv. 37, no. 2, p. 259-270 _dBergamo (Italy) : Istituto Sperimentale per la Cerealicoltura, 1992. _wG444598 _x0025-6153
856	4		_yOpen Access through DSpace _uhttp://hdl.handle.net/10883/1942
942			_cJA _2ddc _n0
999			_c12616 _d12616