Screening tropical and sub-tropical maize germplasm for resistance to Striga hermonthica and S. asiatica and yield-related traits

Abstract

Abstract Identification of maize germplasm with dual resistance to Striga hermonthica (Sh) and S. asiatica (Sa), could lead to the development of cultivars with stable resistance. 130 tropical and sub-tropical maize germplasms were evaluated in a controlled environment for their reaction to Sh and Sa infestations using a 13x10 alpha lattice design with two replications over two seasons. Significant differences (P < 0.05) were detected among the assessed genotypes for all the recorded traits in Sh and Sa-infested treatments. Under Sa-infested conditions, mean Striga emergence counts 8 weeks after planting (SEC8) and 10 weeks after planting (SEC10) were 5.00 and 45.50 respectively, while the mean Striga damage rate 8 weeks after planting (SDR8) and 10 weeks after planting (SDR10) were 3.35 and 3.07, respectively. Under Sh-infested conditions, SEC8 and SEC10 mean values were 3.66 and 3.77, respectively, while the SDR8 and SDR10 values were 5.25 and 2.75 respectively. Positive and significant (P < 0.05) correlations were found between anthesis-silking interval (ASI) and SDR8 (r = 0.18) and SDR10 (0.32) under Sa-infested conditions. Negative and significant correlations were recorded between ear per plant (EPP) and SEC8, SDR8, and SDR10, with r=-0.18, r=-0.27, and r=-0.24, respectively. Under Sh-infested conditions, significant and negative correlations were recorded between SDR8 and EPP (r=-0. 20), EHT and SEC8 (r=-0.22), EHT and SDR8 (r=-0.36), PLHT and SDR8 (-0.48), and PLHT and SDR10 (-0.22). The results suggest that dual resistance to the two Striga species exists in some tropical and sub-tropical maize lines. The following genotypes have dual resistance to Sa and Sh: CML440, CML566, CML540, CML539, CLHP0343, CLHP0326, TZISTR1248, TZSTRI115, TZISTR25, TZISTR1205, TZSTRI113, TZISTR1119, TZISTR1174 and the OPVs B.King/1421, Shesha/1421, ZM1421, DTSTR-W SYN13, DTSTR-Y SYN14, and 2*TZECOMP3DT/WhiteDTSTRSYN) C2. The identified genotypes are suitable for use as parents in developing and deploying high-performing maize varieties with Striga resistance and improved grain yield.