Mutagenic response of rhodes grass (Chloris gayana Kunth.) to gamma rays. II. Studies on second (M2) generation parameters

Abstract

The effect of gamma rays on parameters such as chlorophyll mutation frequency and spectrum, mutagenic effectiveness and efficiency and viable mutation frequency and spectrum were studied in M 2 generation of Rhodes grass employing nine doses of gamma rays . The chlorophyll mutation frequency increased in a linear fashion at low and medium doses and was erratic at higher doses . The chlorophyll mutant spectrum included albina, xantha, chlorina, viridis, tigrina, striata, albo-xantha and albo-viridis . The frequency of these mutants varied with treatments . A dose rate of 60 krad was found to be effective as well as efficient both on M I and M 2 plant basis in inducing chlorophyll mutations . The highest frequency of viable mutations was found in 50 krad treatment. Viable mutants found were: nodal variant, peduncle variant, lax ears, coxcomb ears, earhead proliferation, level of fingers, incurved fingers, gappy ears, apical sterility, partial sterility and high sterility .

Non-arrowing and broad-leaved mutants in Rhodes grass (Chloris gayana Kunth.)

“…1) and broad-leaved (Fig . 2) in highly sterile and partially sterile types respectively, were isolated from M2 viable mutations (KRISHNA et al ., 1984b) . A brief description of the mutants is given below : Non-arrowing type : relatively broad-leaved, short stem length, absence of inflores- cence, heavy tillering and bushy growth habit (in 50 krad) Broad-leaved type : strikingly vigorous, broad-leaved, tall with heavy tillering associated with partial sterility (in 40 Krad) .…”

“…Seeds harvested from the main tiller of M t plants were raised in nursery, screened for chlorophyll mutants and then transplanted in the main field to score viable mutations (KRISHNA et al ., 1984b) . The selected viable mutants in the M 2 generation viz ., non-arrowing and broad-leaved mutants of practical importance were multiplied through rootslips and studied for their forage yield and nutritive quality by proximate analysis .…”