Rooting traits of peanut genotypes differing in drought tolerance under drought stress

Document Type: Research Paper

Authors

1 Shandong Peanut Research Institute, Qingdao 266100, China

2 Taian Academy of Agricultural Sciences, Taian 271000, China.

3 Shandong Peanut Research Institute, Qingdao 266100, China.

Abstract

The effects of two water regimes (well-watered condition or drought stress) on root length,
root surface area and root volume were tested on two peanut genotypes (the drought-resistant
variety HuaYu 22 (HY22) and the drought-sensitive variety HuaYu 23 (HY23)), measured 101
days after sowing. The roots were sampled from the upper (0–40 cm) and deeper (40–100 cm)
soil layers. Root diameter was measured to the nearest 0.5 mm in describing its distribution.
Total dry weight and pod yield were measured at harvest. The drought tolerance index of pod
yield and the harvest index in HY22 were higher than those in HY23. The total root length
density (RLD), total root surface area and volume were significantly higher for HY22 than
HY23. The RLD in the deeper soil layer was lower for HY23 than HY22. Under drought stress,
the percent RLD in the deeper layers increased in both genotypes. Compared to well-watered
condition, the total root surface area and root volume in the upper soil layer were lower under
drought stress and root traits in deeper soil layers were higher. Drought stress had no impact on
very fine roots (diameter < 0.5 mm) of HY22 in the deeper soil layer but lowered their share in
HY23 markedly. The RLD and root surface area in the deeper soil layer were related to the pod
yield of peanut. This finding could be useful in growing peanut under drought conditions.

Keywords