000			03105nab a22003137a 4500
001			G82964
003			MX-TxCIM
005			20220526153018.0
008			121211s1992 it |||p op||| | | eng d
022			_a2279-8013
040			_aMX-TxCIM
041			_aeng
090			_aCIS-4616
100	1		_aVasal, S.K. _95280
245	1	0	_aHeterotic patterns of eighty-eight white subtropical CIMMYT maize lines
260			_aBergamo (Italy) : _bIstituto Sperimentale per la Cerealicoltura, _c1992.
500			_aPeer review
500			_aOpen Access
520			_aHybrid-oriented source germplasm with established heterotic pattern is essential for initiating hybrid development. The objective of this study is to identify and form heterotic groups of maize (Zea mays L.) with subtropical adaptation. Eighty-eight inbred maize lines derived from six CIMMYT subtropical maize populations and pools were crossed to four tester lines, one each from Pool 32 and Populations 34, 42 and 44. The 352 line x tester hybrid combinations were divided into four sets, each set comprising of crosses of 22 lines with the four testers, and evaluated during two seasons at Taltizapan, Mexico during 1989 and 1990. Mean grain yields for the four sets ranged from 9.0 t/ha (set 1) to 8.2 t/ha (set4). General combining abiliti (GCA) and specific combining ability (SCA) for grain yield were calculated by line x tester analysis. Of the 88 lines tested, 14 from Population 44, 11 from Population 42, nine from Pool 32 and one from Population 34 had positive GCA effects for grain yield. Among testers, Tester 2 (Pop. 44) showed positive GCA effects for yield, and Tester 1 (Pool 32) had negative GCA effects for yield. Significant differences were observed for SCA effects for yield in the different line x tester crosses. Several combinations were identified having yields of 10 t/ha or more and possessing high SCA effects. Interpopulation corres generally outyielded and had greater SCA effects as compared with intrapopulation corsses. Superior intrapopulation combinations, however, were observed among crosses involving lines from Population 44. Two heterotic groups STHG "A" and STHG "B" are being formed from these materials using the testcross data. Several of the lines included in this study were announced as CIMMYT maize lines (CML) during 1991 and are made available to our cooperators worlwide. Twelve of the 20 top-yielding single crosses (five from each set) were between CML lines. The matieral and information generated from this study may be useful for future hybrid development work at CIMMYT and in other public and private beeding programs, particularly in the developing world.
546			_aText in English
650		7	_aZea mays _2AGROVOC _91314
650		7	_aGermplasm _2AGROVOC _91136
650		7	_aCombining ability _92367 _2AGROVOC
700	1		_aSrinivasan, G. _96538
700	1		_aHan, G.C. _927600
700	1		_aGonzalez C., F. _927601
773	0		_tMaydica _gv. 37, p. 319-327 _wu444598 _dBergamo (Italy) : Istituto Sperimentale per la Cerealicoltura, 1992. _x2279-8013
942			_cJA _2ddc
999			_c26133 _d26133