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

on overall performance, ~ of the best progenies were used in the following winter season to
synthesize progenies for the next cycle of evaluation. In addition, using 4'; selection intensity,
location specific and across location improved varieties in each of the populations were
synthesized. These improved varieties were evaluated in advanced generation trials. After
comprehensive evaluation, the promising ones were released for commercial cultivation.
Improved varieties of various populations were compared with their respective base
populations at different cycles of selections. Gains realized through selection showed a great
deal of variation. In a few populations no improvement was recorded, while in others, general
gains of 3-5'; per cycle of selection were recorded. Gains were rather high in composite Diara
(an extra early variety) from which three improved versions have been subsequently released.
From studies of the various popul~tions under improvement, it was noted that the varieties
selected on across location testing gave better stability and higher grain yield than those of
location specific ones. It was also obserVed that the use of advanced generation full-sib
progenies in general yielded higher than those from F1 seed material. Based on this observation,
full-sib progenies in several populations were advanced to F2 in the summer season. The next
cycle, progenies as well as improved varieties were developed in the ensuing winter season using
F2 seed. Thus, through this process, one cycle of full-sib selection is completed in two crop
seasons (summer and wi nter) .
Developnent of maize varieties for specialized uses.
The starch industry has expressed a need for developing waxy (high amylopectin) and high
oil content varieties. Considerable progress with waxy maize has been made and a number of waxy
maize varieties are under advanced stages of evaluation. Preliminary evaluations indicate that
the waxy types yield 10-15'; less than the best normal materials. WOrk on high amylose types is
also in progress.
Normally, maize contains 3.0-5.4'; oil which is highly un~aturated (Table 4). Some of the
high oil selections obtained from the USA have been under per 5e evaluation and as parents of
double top cross hybrids. While these introductions per 5e have limited commercial use, some of
them can be used in hybrid combinations. A few hybrids have shown 1.5-2.0,; increase in oil
content with yield levels comparable to the check hybrid.
Varieties for forage.
Little work has been done on the development of maize varieties suitable for forage.
Composite varieties like Kisan and Vijay were being cultivated and also used for forage, as they
possess dark green foliage. By mobilizing the tropical germplasm, a new composite "Afric/J/1 Tan"
has been developed which is very popular as fodder maize. It is a full-season composite with
abundance of foliage and good seed yield. Yields of 1 t/ha per day of green forage has been
reported at Kolhapur (Maharashtra) and several other places. This composite is suitable for
cultivation in both summer and winter seasons. It possesses white dent grain and long ears.
A simple recessive gene bm 3
with distinct morphological marker is known to reduce the
lignin content of fodder and increase its digestibility. This gene was incorporated into the
genetic background of a number of elite population of various maturity groups. The selection
with bm 3
had lower lignin content and higher in vitro digestibility, compared to the normal types
at various stages of crop growth. The reduction in lignin in different maize varieties varied
from 2 to 3,;, while the in vitro digestibility was improved by 2-5';.
Winter maize program.
Research carried out at various research stations of the AICMIP has shown that winter
maize can be successfully grown in almost all parts of India except the hilly regions. The
yields obtained during the winter season are substantially higher than those of the summer crop.
Yield levels of 8-10 t/ha have frequently been obtained. However, yield of 4-6 t/ha in farmer
fields is not uncommon. Based on this convenient situation, the AICMIP now regularly conducts
trials in winter. Thus the research stations (except those of Zone I) are engaged in breeding
activities of cultivars suitable for winter season and regularly carry out two sets of trials, in
summer and winter seasons. This testing is needed to explore the possibilities of further
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