The study was conducted at farmers’ field of Itbaria, Patuakhali sadar Upazilla in the Patuakhali district, the coastal region under the agro ecological zone AEZ-13 (Ganges Tidal Flood plain) which is located between 22°14' and 22°29' North latitudes of Bangladesh. The experiment was setup during January to April 2016 in the Rabi season (October to March). Rabi season (October to March) is characterized by comparatively low temperature and plenty of sunshine from November to February. Particularly in the areas of southern coastal region, mungbean crop could be grown in late Rabi (winter period) from mid January to mid February. The winter period is short in this area due to close proximity to the Bay of Bengal. The experimental site is also adjacent to the Bay of Bengal. The area lies at 0.9 to 2.1 metre above mean sea level (Iftekhar and Islam, 2004). The soil of the experimental area was non-calcareous and slightly saline (2.6 dS/m), silty clay in texture and neutral in reaction (pH 6.7). Fertility status of soil in general is poor with a low level of organic matter (1.56). Total nitrogen (0.105%) level in soil is low, phosphorous (4.69%) very low and potassium (0.40%) high. Land type is medium high land and the major area (74.6 %) is medium high land (SRDI, 2005).
Experimental layout and Plant materials
The experiment was laid out in a randomized complete block design (RCBD) with 3 replications. Each replication represented a block which was divided into fifteen unit plots. The unit plots (4 m x 2.5 m) were made ready as per design with a distance of 0.5 m between the plots and 1 m between the replications. Fifteen (15) Mungbean varieties were randomly allotted to the plot within a block. The seeds of mungbean varieties viz., BARI Mung-1, BARI Mung-2, BARI Mung-3, BARI Mung-4, BARI Mung-5, BARI Mung-6 were collected from Bangladesh Agricultural Research Institute (BARI), Gazipur, BINA Moog-4, BINA Moog-5, BINA Moog-6, BINA Moog-7, BINA Moog-8 from Bangladesh Institute of Nuclear Agriculture (BINA), Mymensingh, BU Mug-1, BU Mug-2, BU Mug-4 from Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU), Gazipur and Patuakhali local Mung variety from farmers’ of Patuakhali. BARI, BINA and BSMRAU have developed mungbean varieties (Source: www.bari.gov.bd, www.bina.gov.bd and www.bsmrau.edu.bd: Dept. of Agronomy, respectively) but these varieties earlier not tested properly in coastal region. The varieties and their important characteristics are presented below:
BARI Mung-1: This variety was introduced from India (M-7706). Plant height: 45-50 cm. Tolerant to CLS. Photo insensitive. Protein: 25.50%, CHO: 47.30%. Head dhal yield: 72.0%. Cooking time: 14 min. Seed color is green. 1000 seed weight: 25.40 g. Seed yield: 0.9-1.0 t ha-1. Duration: 65-70 days.
BARI Mung-2: This variety was introduced from Philippine (M-7715). Plant height: 45-52 cm. Tolerant to YMV and CLS. Photo insensitive. Protein: 22.56%, CHO: 46.15%. Head dhal yield: 76.1%. Cooking time: 15 min. Seed color is green. 1000 seed weight: 25.33 g. Seed yield: 1.1-1.35 t ha-1. Duration: 65-70 days.
BARI Mung-3: This variety was developed from crossing between Sona mung and BARI Mung-2. Plant height: 50-55 cm. Tolerant to YMV and CLS. Photo insensitive. Protein: 20.81%, CHO: 49.53%. Head dhal yield: 67.5%. Cooking time: 15 min. Seed color is brownish green. 1000 seed weight: 29.4 g. Seed yield: 1.0-1.3 t ha-1. Duration: 60-65 days.
BARI Mung-4: This variety was developed from local cross (BMX 841121). Plant height: 52-57 cm. Resistant to YMV and CLS. Photo insensitive. Protein: 23.1%, CHO: 51.32%. Head dhal Yield: 68%. Cooking time: 17 min. Seed color is green. 1000 seed weight: 31.9 g. Seed yield: 1.2-1.4 t ha-1. Duration: 60-65 days.
BARI Mung-5: This variety was introduced from AVRDC (NM- 92). Plant height: 41-46 cm. Resistant to YMV and CLS. Photo insensitive. Protein: 20.93%, CHO: 49.46%. Head dhal Yield: 68%. Cooking time: 18 min. Quite Synchrony in maturity. Seed color is deep green. 1000 seed weight: 41.9 g. Seed yield: 1.40-1.45 t ha-1. Duration: 58-60 days.
BARI Mung-6: This variety was introduced from AVRDC (NM- 94). Medium plant stature. Plant height: 40-45 cm. Resistant to YMV and CLS. Photo insensitive. Bold seed size with green seed coat. Protein: 21.2%; CHO: 46.8%. Head dhal Yield: 67.2%. Cooking time: 18 min. Synchrony in maturity and late potentiality. Recommended for cultivationin in Jessore, Khulna, Faridpur, Pabna, Rajshahi and Dinajpur. Seed color is deep green. 1000 seed weight: 40.0 g. Seed yield: 1.5 –1.6 t ha-1. Duration: 55-60 days.
BINA Moog-4: A high yielding winter mungbean variety, released in 1997. Plant height: 28-32 cm. It matures between 75-80 days. Seed size is bigger than Bina moog 1. All the pods mature at a time. Protein: 23.0%. Plants are short and tolerant to CLS and YMV. Pods have prominent ridges. Seed color is dull green. 1000 seed weight: 37.50 g. Maximum seed yield potential is 1.2 t ha-1 (av. 1.1 t ha-1).
BINA Moog-5: A late winter-cum-summer mungbean variety, released in 1998. Plant height: 40-45 cm. It matures between 70-80 days. Seed is green shiny and bigger than BINA Moog-1. Almost all the pods mature at a time. Protein: 23.0%. Seed color is bright green. 1000 seed weight: 35-40 g. Plants are short and tolerant to CLS and YMV. Maximum seed yield potential is 2.0 t ha-1 (av. 1.5 t ha-1).
BINA Moog-6: This is an early mature summer mungbean variety, released in 2005. Plant height: 35-40 cm. It matures between 64-68 days. Almost all the pods mature at a time. Protein: 23.0%. Seed color is bright green. 1000 seed weight: 35-40 g. The variety is tolerant to CLS and YMV. Average yield is up to 1.5 t ha-1.
BINA Moog-7: This is a high yielding summer mungbean variety, released in 2005. Plant height: 40-45 cm. It matures between 70-74 days. Almost all the pods mature at a time. Protein: 23.0%. Seed color is green. 1000 seed weight: 35-40 g. The variety is tolerant to CLS and YMV. Average yield is up to 1.8 t ha-1.
BINA Moog-8: This is a summer mungbean variety, released in 2010. It is obtained from seeds of MB-149 which were irradiated with 400 Gy dose of gamma ray. Maturity period ranges from 64-67 days. Maximum grain yield is about 2.0 t ha-1 (av. 1.8 t ha-1). Seed is medium size with green shiny color. Seed contains higher protein (23%). Plants are short and tolerant to YMV. This variety is suitable for cultivation in pulse growing areas of Bangladesh.
BU Mug-1: This variety was developed from AVRDC- VC 6372 (45-8-1). Plants are short. Almost all the pods mature at a time. Resistant to YMV and CLS. Leaf and seed color is deep green. Seed yield: 1.40-1.60 t ha-1. Duration: 55-60 days.
BU Mug-2: This variety was developed from AVRDC- VC 6370 (30-65). Plants are short. Almost all the pods mature at a time. Resistant to YMV and CLS. Leaf and seed color is deep green. Seed yield: 1.50-1.70 t ha-1. Duration: 55-60 days.
BU Mug-4: This variety was developed from AVRDC- GK 7. Plants are short. Tolerant to high moisture and rainfall in soil. Almost all the pods mature at a time. Resistant to YMV and CLS. Leaf and seed color is deep green. High moisture and rainfall. Seed yield: 1.80-2.00 t ha-1. Duration: 55-60 days.
Land preparation and Fertilizer application
The land was prepared at ‘joe’ condition by deep ploughing and cross-ploughing 4 times by power tiller followed by laddering until the desired tilth. All the weeds, residues and stubbles of the previous crops were removed from the field and the large clods were broken into smaller pieces to obtain a desirable tilth of soil for sowing of mungbean seeds. The fertilizers were applied as per fertilizers recommendation guide (BARI, 2011). Urea, TSP and MoP were applied in the field uniformly @ 50-85-35 kg/ha, respectively during the final land preparation. The fertilizers were then mixed properly with the soil by spading and individual unit experimental plots were leveled.
Seed sowing and Intercultural operations
The mungbean seeds were sown on the 29th January, 2016 at the rate of 30 kg/ha (BARI, 2011) with making rows maintaining spacing (30 cm x 10 cm) for mungbean cultivation. Seed sowing was done at a depth of 6-7 cm and the seeds were covered by loose soil with the help of hand. All intercultural operations were done as and when necessary to ensure normal growth and development of crops.
Yield and yield attributing data collection of different mungbean varieties
Five plants were selected at random from each plot to measure plant height (cm), number of branches plant-1, number of leaves plant-1, number of pods plant-1, pod length (cm), number of seeds pod-1 (5 pods), 1000 seed weight (g). Plant height was measured from the base of plant upto the top of the main shoot at reproductive stage and the mean plant height was expressed in centimeter (cm). Number of branches plant-1 and number of leaves plant-1 were counted from the inner rows of each plot at reproductive stage and were averaged. Number of pods plant-1 was counted from each plot at the ripening stage and average number of pods per plant was calculated. Pod length was measured by a meter scale from randomly selected 5 pods after harvesting. Mean value of them was calculated plot wise and the mean pod length was expressed in centimeter (cm). Number of seeds per pod was recorded after harvesting of the crop from the randomly selected 5 pods from pre-selected 5 plants and was calculated from their mean values. 1000 grains were collected from randomly selected 5 plants of each plot and were weighed in gram by digital electric balance. Mature pods manually harvested by hand in Bangadesh when about 80% of the pods became blackish in colour. Grains obtained from 1m2 (1m x 1m) area from the selected portion of the center of each unit plot that was harvested from the plots. The harvested pods of 1 m2 area from each unit plot were kept separately. The pods were properly dried in the sun, then beaten with a stick and threshed. After threshing, grains were recorded from 1 m2 area per plot wise and the yields were expressed in kg ha-1.
Statistical analysis: The collected data were statistically analyzed through the analysis of variance using Web Agri Stat Package (WASP 1.0). Means were separated by critical difference (CD) values at 5% level of significance.