Thirty CGMS lines and their respective maintainer lines were evaluated for floral characters. The traits studied were days to 50% flowering, glume angle, panicle exsertion percentage, stigma exsertion percentage, pollen sterility percentage, awning, spikelet fertility percentage and out crossing percentage. All the genotypes showed significant variation for the traits studied. Out of 30 CGMS lines, 15 CGMS lines were found to be completely pollen sterile, while others showed spikelet fertility ranging from 0.25 to 1.30%. The CGMS linesIR 72081A, IR 75596A, IR 75601A, IR 75608A, IR 80154A, IR 80559A, CRMS 32A, APMS 6Awere found to be promising for the characters of glume angle, panicle exsertion percentage, stigma exsertion percentage, pollen sterility percentage, natural out crossing rate and medium duration. These CGMS lines may be further studied and utilized for three-line hybrid rice production technology.

In self-pollinated crops hybrid breeding is difficult, because floral traits are unfavorable for out crossing. As rice is the principal food crop of India, population explosion stresses the need to increase the productivity of rice crop. Among the different improved technologies to increase the productivity of rice, the exploitation of hybrid technology appears to be promising.

However, all lines do not perform equally well and also give variable heterosis with restoration. Thus, the characterization of cytoplasmic genic male sterile lines for floral traits is one of the important aspects that a breeder should keep in mind while selecting a line in hybrid breeding. Chinese rice scientists developed rice hybrids utilizing CGMS, while increased yield by about 20% over semi-dwarf varieties (Yuan et al., 1994). The desirable floral traits for male sterile lines studied were days to 50% flowering, glume angle, panicle exsertion percentage, stigma exsertion percentage, pollen sterility percentage and out crossing percentage. Therefore, the present study was conducted with an objective to evaluate CGMS lines for floral characters at Centre for Plant Breeding and Genetics, Tamil Nadu Agricultural University, Coimbatore.

Thirty CGMS lines of rice (Oryza sativa L.) of diverse sources were raised during September 2007 at paddy breeding station, Tamil Nadu Agricultural University, Coimbatore. All the lines were grown in three replications in randomized block design and a spacing of 20x20 cm was adopted. Observations were recorded for five florets of different plants for floral traits in all the genotypes. The traits, namely, days to 50% flowering, glume angle, panicle exsertion percentage, stigma exsertion percentage, pollen sterility percentage, awning, spikelet fertility percentage and out crossing percentage were studied by routine procedure. About 10-15 spikelets from the freshly emerged panicles of all the 12 plants were collected and examined under microscope with 1% Iodine Potassium Iodide (I-KI) solution for pollen sterility assessment. Five panicles per plant were evaluated for natural seed set percent. Panicles emerging from the sheath were bagged with butter paper bags prior to anthesis to prevent cross-pollination. Bagged panicles were harvested to assess seed setting percent.

Genetics & Evolution Journal, Iodine Potassium Iodide, I-KI, Floral Traits, Hybrid Rice Production Technology, Pollen Sterility, Self-pollinated Crops, Continuous Glucose Monitoring System, CGMS, Cytoplasmic Genic Male Sterile Lines, Hybrid Technology, Stigma Exsertion, Panicle Exsertion, Spikelet Fertility.