National Research Centre for Sorghum and All India Coordinated Sorghum Improvement Project, IARI - Regional Station, Hyderabad-500 030
1Present address: Agricultural Research Station, Adilabad (A. P.).
2Present address: Andhra Pradesh Agricultural University, Rajendranagar, Hyderabad-500 030 (A. P.).
Heterosis for root activity in sorghum hybrids exhibited different patterns. Heterosis for root activity in CSH-1 was marked at the knee-high stage. As the lateral distance increased from 5 to 20 cm, heterosis for root activity was deeper and deeper, being upto a depth of 14 cm at L1 (5 cm), 28 cm at L2 (10 cm) and 32 cm at L3 (20 cm). Maximum heterotic activity at knee-high stage was at 10 cm depth. At flowering no heterosis for root activity was observed in CSH-1. In CSH-2 heterosis persisted at flowering as well. Unlike in CSH-1 heterosis for root activity at knee-high stage was deeper between 12-22 cm depth and at flowering it extended to surface layers also. Possible relationship between predominantly gca for yield heterosis in CSH-1 and sca in case of CSH-2 and the different patterns of root activity is discussed.
The male sterile and its fertile counter part exhibited distinct differences in root activity. The greater drought resistance of A line correlates well with its pattern of root activity compared to the B line. The role of cytoplasm in influencing root activity needs to be investigated.
