An experiment was conducted at the field laboratory of Bangladesh Institute of Nuclear Agriculture, Mymensingh to investigate the morpho-physiological characters, yield attribute and seed yield in seven advanced mustard mutants viz., RM 01, RM 02, RM 03, RM 04, RM 05, RM 10 and RM 11 along with a cultivar BINA sarisa-4. The experiment was laid out in a Randomized Complete Block Design with three replications. Results revealed that plant height, leaf area index (LAI) and absolute growth rate (AGR) differed significantly at all growth stages. LAI and AGR increased till 60 days after sowing (DAS) followed by a decline due to leaf shedding at later growth stages. The mutant RM 05 showed superiority in respect of LAI and growth parameters like AGR at most of the growth stages and also produced the highest seed yield whilst RM 01 and RM 10 showed the inferiority in case of plant height, LAI and AGR. Moreover, high yielding genotypes showed superiority in leaf chlorophyll content, photosynthesis; total sugar content and nitrate reductage activity. RM 05 produced higher number of siliqua plant-1 resulting higher seed yield achieved. Among the mutants/cultivars, RM 05 produced the highest seed yield due to morpho-physiological superiority than the others.

Key words: Mustard, mutants, evaluation, growth and yield attributes.

Introduction Brassica oil crop is the most important that supplies major edible oil in Bangladesh (BBS, 2009). It covers about 80% of the total oilseed acreage and about 71% of the total production (BBS, 2009). In Bangladesh, the seed yield of mustard is about 760 kg ha-¹ which is very low in comparison to other developed countries (2400 kg ha-¹) (FAO, 2007). The low yield is due to lack of high yielding varieties and improper agronomic practices. An understanding of some morpho-physiological characters in mustard is necessary to make progress in genotypic improvement and for the management of the crop either to increase yield and quality or to reduce the cost of production. Important physiological attributes such as leaf area index (LAI), crop growth rate (CGR), relative growth rate (RGR), net assimilation rate (NAR) and specific leaf weight (SLW) can address various constraints of a variety for increasing its productivity (Tandale and Ubale, 2007). In Bangladesh, several research Institutes like BARI, BINA and BAU have developed a couple of varieties of mustard which are high yielding compared to local landrace. Recently, BINA has developed several promising mustard genotypes of high yield potentials. These genotypes need to be assessed for their physiological growth and morphological maneuvering that takes place compared to the existing mustard cultivars. The present research work has been designed to study the different growth parameters and other morpho-physiological characteristics responsible for higher biological yield as well as their interrelation to the grain yield. Overall objectives of the research work were to evaluate the growth and development of seven elite mustard genotypes compared to the existing variety, BINAsarisa-4; and to select better genotype in respect to growth and yield components.