REACTIONS OF MAIZE GENOTYPES TO USTILAGO MAYDIS (DC) CORDA

Abstract

Maize production in Tanzania has still been relatively low due to limiting factors such as diseases. Maize smut caused by Ustilago maydis is among those diseases. This study aimed to determine response to U. maydis by maize genotypes cultivated in Sengerema district, Tanzania. Five (5) maize genotypes, namely SEEDCO SC 419, ZAMSEED ZMS 402, PIONEER PHB 3253, LUBANGO HYBRID, and GEMBE were selected for use in the study. Control plots were established for yield loss quantification. 2mls and 3mls (1 × 106 teliospores mL-1) were injected into apical node of 60cm tall plant and into the ear silk of plant before pollination respectively to ensure uniform infection and thus eliminate disease escapes. Maize smut disease was assessed based on its symptoms and signs. Data on the smut incidence, severity, number of kernels per cob, total grain weight, yield, and yield loss were collected. Smut disease incidence, severity and yield loss had significant impact among the tested genotypes (p<0.001). The highest and lowest average disease incidence was in GEMBE (5.22%) and ZAMSEED ZMS402 (0.66%) respectively. While the highest and lowest mean severity were in GEMBE (2.48cm) and SEEDCO SC 419(0.07cm) respectively. The average yield loss for SEEDCO SC 419 was 51.89% recorded as the lowest. While for the ZAMSEED ZMS402 was 65.17% recording as the most susceptible. Based on the results SEEDCO SC419 was the most tolerant genotype to U. maydis. Differences in susceptibility levels among the maize genotypes is an important factor influencing U. maydis infection success.