RA 00048.pdf - OAR@ICRISAT

grain was assessed for grain mold by (1) visually rating grain for external discoloration, (2) plating surface-sterilized
grain to determine fungal infection, and (3) analyzing grain for ergosterol content to determine total fungal biomass.
Fusarium moniliforme, F. semitectum. Curvularia spp and Alternaria spp were the predominant fungi isolated. The
greatest number of fungal colonies and highest ergosterol content were associated with misted seed at harvest
maturity. Greater differences in fungal invasion among varieties were found with ergosterol analysis than with the
plating technique. Visual assessment of grain mold was more closely correlated with ergosterol levels than with total
fungal colonies or percent infection.
Sorghum Improvement in Association with Maize
Rene Clara, Napoleon V. Casamalthuapa, Rogelio H. Cordova, Erlberto C. Amaya,
and Vartan Guiragossian
Abstract
Sorghum is the second most important cereal (following maize) in Central America. It is most commonly intercropped
in a one to one ratio with maize; for example, about 9 4 % of the sorghum sown in Guatemala is intercropped with
maize or beans. Sorghum flour is made into tortillas directly but generally blended into flour from maize. The degree of
blend is influenced by the availability of maize and the market price—if the price of maize is high, it is sold and the
percentage of sorghum locally consumed increases.
The sorghum improvement program in El Salvador has most extensively used introductions from Texas A & M
University, ICRISAT Center, ICRISAT-CIMMYT, and Puerto Rico directly and in combination with locals to derive
earlier, shorter varieties with better grain quality. Selection and evaluation is undertaken in the intercrop. Sorghum is
sown in maize and they are in competition for about 68 days when the maize stalk is broken below the ear—at this
time the maize is 90 days old. It has been found that the sorghum-maize intercrop (distance between maize-sorghum
rows is 45 cm) is more profitable than either as a monocrop. Improved shorter varieties yield 5 0 % more in sole crop
and 3 5 % more in the intercrop than local varieties. Best yields are obtained when the maize matures in about 90 days.
The lines from El Salvador, ES-412 and SM-1, have been evaluated in Mexico and found to have good quality for
making tortillas.
Soil Factors and Sorghum Population Optima in
Botswana
M. J. Jones, D. Raes, J. Sinciair, and I. Makin
Abstract
In sorghum row-spacing/population trials in Botswana, soil factors strongly influenced crop response to the rainfall
pattern. Higher populations had higher rates of water use than low populations on a loamy sand but not on a sandy
loam, in which rooting appeared to be restricted by a naturally high bulk density. On this compact soil high populations
showed severe drought stress with consequent loss of yield potential, and yields peaked at about 63 000 plants/ha;
but on the loamy sand yields increased with population up to at least 140 000 plants/ha. It is postulated that crop
performance in a semi-arid environment depends heavily on the ability of the soil to act as a buffer against drought,
and this is a function not only of soil depth and water-holding capacity but also ease of rainfall infiltration and root
proliferation. Such factors are highly relevant in extension advice to farmers and in land capability evaluation.
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