Forage production in sorghum and millet: growth variables.
Six commercial varieties of sorghum (Sorghum
vulgare) and one of millet (Pennisetum americanum), as well
as six millet lines from The International Crop Research
Institute for the Semiarid Tropics (ICRISAT), Hyderabad,
India, were evaluatedTo identify materials of sorghum and
millet suitable for forage production during the springsummer
period, and to determine the determinants of crop
yield,. Crop Growth Rates (CGR), Relative Growth Rates
(RGR) and Net Assimilation Rates (NAR) were estimated.
Total Dry Matter (TDM) was positively and highly correlated
to CGR in both harvests, but TDM was not significantly
correlated with RGR or NAR during the first harvest. The
only significant correlation during the second harvest was
between TDM and NAR (-0.730). CGR in the second harvest
was highly correlated (r = 0.932) to Leaf Area Index (LAI)
during this harvest, but not during the first one. The largest
correlation observed for CGR during this harvest was with
crop height at first harvest (r = 0.763). For both harvests LAI
and Specific Leaf Area correlated directly with TDM in a
highly significant manner, while Leaf Weight Ratio
correlated inversely TDM. It was concluded that CGR was
the main determinant of dry forage yield.