Proceedings of the Fifth Asian Regional Maize Workshop - Search ...

Even though originally eight broad based gene pools have been developed, many more are in
developmental stages to meet the specific needs of the breeding progr8lllS. For instance, it is a
priority for the AICMIP to generate a pool for building up multiple disease resistant stocks,
increasing the frequency of favorable alleles for stalk borer, and a pool to improve resistance
to soil moisture stresses.
Enhancing tolerance to inbreeding and development of single cross hybrids.
Many measures have been taken to enhance the hybrid performance and tolerance to inbreeding
depression in heterotic populations with the aim to produce Vigorous inbred lines viable
enough for seed production, as to be utilized in production of single cross hybrids. The
existing heterotic pools and synthetics did not respond very satisfactorily to inbreeding
depression. Introduction of a selting phase in the intrapopulation improvement progr8lll helped in
eliminating deleterious recessives and also in improving tolerance to inbreeding depression of
the genotypes. To enhance the cross performance, interpopulation improvement was initiated in
those populations known to belong to different heterotic patterns.
It is a matter of great satisfaction that based on this approach, a three way hybrid
(Trishulata) has been released for cultivation to the farmers. Also, many full season,and early
maturing double cross, three-way, and single cross hybrids have shown a very high productivity
level under experimental conditions. These are presently in the advanced testing stage and will
soon be released both for summer and winter cultivation (Tables 5-9).
Tab1e 5. Performance of ear1y maturi ng three-way hybri ds at Pantnagar (Pant), A1mora (A1m) and
Udaipur (Udai). 1992 SUmmer.
Yield (kg/ha)
" over
Pedigree Pant Alm Udai Mean check
EHF 1061 4168 7721 1709 4533 11.43
(0741 x 1-2-4-1-2 x Tarun
x 36-1-1-4) x 0831 4219 6391 2554 4388 7.86
EHF 1101 3485 7734 1486 4235 4.10
Navin (check) 3681 6306 2218 4068
Table 6. Performance of early maturing experimental single cross hybrids. 1992 summer.
Yield (kg/ha)
" over
Pedigree Pant Alm Udai Mean check
0832 ® 41-1-1-2-1 x
0831 ® 60-2-2-1-1 4798 6731 2883 4804 32.09
Tarun @ 83-1-3-2 x
0831 039-2-1-1 5217 6663 2436 4772 31.20
0831 QS) 140-1-2-1 x
Suw. 1 @ 201-1-1-2 4452 6912 2603 4656 28.02
0741 ® 1-2-3-2-1-3 x
Tarun ® 50-1-1-1-2 4287 6227 3312 4622 27.08
VL 42 (check) 3035 6211 1665 3637
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