Genetic Analyses And Gene Tagging Of Maize Cob Color Mutant Obtained By Radiation

Maize is the most important crop in China; the yield has a significant influence to the national economy. The gene that controls the maize cob color was associated with the yield. Hence, it would be great significant to the maize breeding by researching the genetic characters of a new cob color mutant and knowing it’s inheritable mode. The major characters of698-3R, a mutant with red cob derived from inbred line698-3by irradiation, was comparatively analyzed to the original maize inbred line698-3with white cob color; The genetic identification of cob color mutant was carried out using genetic mating design, expect to clear on the inheritance; and the gene controlled cob color was mapped preliminary by SSR-BSA. The main results were as follows:1. Phenotypic character researches showed that, the cob glume of698-3R is red while inbred line698-3is white. On the other agronomic characters, compared with inbred line698-3,698-3R has smaller degree of leaf angle, indicate that is a compact plant type; and also698-3R have shorter spindle length, secondary branch number decrease, smaller tassel, that is beneficial to increase yield; ear length and100-kernel weight were significantly reduced, kernel numbers significantly increased, barren ear tip length significantly shorten, hence the yield increased significantly. The results are consistent with the previous research result that red cob color is associating with the high yield.2. The genetic analytic result showed that, all the F1plants of reciprocal crosses have red cob, indicated the red cob was controlled by nuclear dominance gene, the segregating ratio of red cob plants to white cob plants in the F2and backcross population with reciprocal crosses are correspond to the theory expect ratio of a single gene inherent, demonstrate the red cob trait of698-3R was governed by a single dominance gene, and it is temporary named as C (t).3. The C (t) gene is preliminary positioned between the SSR markers phi095and umc1452through the SSR-BSA analysis; it was located on the short arm of chromosomel. The gene C (t) is linked to phi095with genetic distance3.9cM, and umc1452with genetic distance7.1cM. The C (t) gene controlled red cob color of698-3R in this study is closed to the SSR primer phi095of P1gene, indicated that C (t) gene is closely linked to major P1gene which control pericarp color and cob color in previous research. However, the homology between this red cob mutant gene C (t) and P1gene needs further investigation.