INVESTIGATION OF ETHREL GAMETOCIDE IN FINGER MILLET (Eleusine coracana, L. Gaertn) HYBRIDS THROUGH GENETIC ANALYSIS

Abstract

Finger millet is a staple food crop of in Africa due to; desirable attributes like being highly nutritious, good grain storagability and strong cultural value. In Kenya, therefore, finger millet is on high demand for food, culture and trade. Low yield due to poor genetic potential varieties necessitate breeding for better varieties. Due to its floral architecture, finger millet is mostly self- pollinating with only 1% chances of cross pollination thus difficult to hybridize. Several plant emasculation techniques including mechanical, genetic and chemical exist, and applied depending on crop species, genetics and floral architecture. The study objectives were to determine optimal ethrel GL for effective emasculation and hybridization; determining the effect of ethrel on agronomic traits and identifying true F1 hybrids from parent selfs using morphological and molecular techniques. This study investigated ethrel efficacy at three levels (1,500ppm, 1,750ppm and 2,000ppm) against 0ppm check in a 6x6 diallel crossing of six elite Kenyan varieties Okhale-1, Gulu-E, KACCIMI 72, IE 2872, IE 4115 and U-15 having contrasting traits. Ethrel was applied in a screen house at Zadoks plant developmental stage 45. The female parent harvested (F1) seeds were planted and post emasculated generation screened in the field using morphological traits, and in the laboratory using molecular techniques, to identify hybrids. Field screening, involved evaluation of head to row plantsfrom female parent pollinated heads in parent pair blocks for successful crosses and possible gametocide effect on post emasculated generation. Morphological heterozygote success rate in the treatments was significantly highest at 2,000 ppm (63.98%), followed by 1,750 ppm (29.78%), 1,500 ppm (9.66%) and least at 0 ppm (1.65%). In the molecular screening, four different Single Nucleotide Polymorphism (SNP) markers were used to detect hybrids at F1. Heterozygosity level in F1s from selfs was effective with 2,000ppm (5.05%) being the highest followed by 1,750ppm and 1,500ppm (4.58%) and 0ppm having the least (4.27%). The optimal GL concentration that resulted in high hybrids was 2,000ppm. Ethrel gametocide affected some physiological growth factors of finger millet like plant height, ear exertion length and grain weight, but, has no effect on post emasculated and residual generation. Further studies should be done beyond 2,000ppm to see the difference in success rate. In order to check on progeny segregation F2 and subsequent generations should be planted further.