ABSTRACT

An experiment was conducted to evaluate the application of plant growth regulator (GABA) on the variation in growth, yield and yield attributes of chilli cv. Narikalkhola under the regional condition of Mymensingh, Bangladesh. The experiment comprised of three levels of GABA viz. 1, 2, and 3 mgL^–1 and fresh water sprayed as control on chilli plant at 30 DAT. The experiment was laid out in a Randomized Complete Block Design (RCBD) with three replications. The application of GABA significantly increased the plant height, number of branches and leaves plant^–1, canopy area, root length, weight of root, stem and leaf as well as the total dry mass over control. GABA @ 3 mgL^–1 had the most effective approach for obtaining the highest significant impact on green fruit yield due to increased number of fruits plant^–1 and fruit size followed by      2 mgL^–1 with same statistical rank while control treatment was the least significant impact on the above traits.

Key words: Chilli, GABA, growth, yield       

Introduction

Chilli (Capsicum annuum L.) belongs to the genus Capsicum and the family Solanaceae. Chilli is native of Central America and the West Indies but spread quickly throughout the tropical countries after the discovery of America and the West Indies (Pruthi, 1993). It is virtually an indispensable item in the kitchen for everyday cooking. The red chilli fruit contains 15.9% protein, 31.6% carbohydrate, 50 mg/100g vitamin-C and small quantities of vitamin A, B and E. In Bangladesh, chilli ranks 1^st in area (349 thousand acres) and 2^nd in production (2,54,000 m tons) among the spices (BBS, 2007). Chilli is widely grown in all parts of the country and its winter production covers about 70% of the total production (BBS, 2007). But the average yield of chilli in Bangladesh is very low compared to other leading chilli growing countries in the world (FAO, 2005) due to improper cultivation management practices. Improvement of existing spice crops through proper cultural management practices need urgent attention to meet increasing demand of edible spices for the fast growing population of Bangladesh. That is why, special attention should be made for increasing the yield per unit area by adopting improved technologies and management practices. In this connection, use of plant growth regulators (PGRs) might be a useful alternative to increase crop production. Many developed countries like Japan, China, Poland and South Korea etc. have long been using PGRs to increase crop yield. PGRs are being used as an aid to enhance crop yield (Nickell, 1982). Among the PGRs, GABA is a new plant growth regulator that may have many uses to modify the growth, yield and yield attributes of plant. GABA contains 1% GA₃ and 0.05% STC (Kamuro et al., 2001) which have capability to enhance the growth and yield attributes in sesame (Islam, 2007), in mungbean (Begum, 2006), in rice (Afroz, 2005), in onion (Rahman, 2005) and in soybean (Rahim, 2005). Research works with GABA on growth, yield attributes and yield of chilli are scanty. So, there is ample scope of conducting research with GABA for increasing yield of chilli. Considering the above facts, the present research work was undertaken to observe the effect of GABA on growth, canopy structure, yield attributes and yield in chilli and to find out the effective dose of GABA for getting the higher yield.

ABSTRACT

Plant growth regulators (PGRs) are used in cotton production to optimize yield and quality and even suppressing excess growth whenever necessary. Experiments were conducted in 2017 at Cotton Seed Multiplication, Training and Research Farm, Sreepur, Bangladesh to study the response of cotton yield and quality to different plant spacings, concentration and time of application of mepiquat chloride (MC) growth regulator. Plant spacings like 45 cm × 30 cm, 60 cm × 30 cm and 75 cm × 30 cm; MC spray @ 1.0, 2.0, 3.0 and 4.0 ml  L^-1  water at 25, 50 and 75 DAE for each concentration along with water spray as control, were the treatment variables. The maximum LAI (0.80) was obtained from 75 cm × 30 cm spacing and the minimum LAI (0.74) was from 60 cm x 30 cm spacing. LAI was maximum (0.90) for plants grown without MC. Plants grown with application of MC 2 ml L^-1 water at 25 DAE produced the minimum (0.64) Leaf area index evaluated highest (1.06) from 2 ml MC L^-1 water sprayed at 25 DAE with 60 cm x 30 cm spacing and lowest (0.52) from 2 ml MC L^-1 water at 25 DAE with 45 cm × 30 cm spacing treatment combinations. So, cotton cultivation in Sreepur, Gazipur areas may be accelerated with foliar application of mepiquat chloride @ 2 ml L^-1 water at 25 DAE along with plant spacing of 60 cm x 30 cm for higher yield and quality.

Key words: Plant spacing, growth regulator, time of foliar, leaf area index, cotton.