M. Monjurul Alam Mondal
Crop Physiology Division, Bangladesh Institute of Nuclear Agriculture, Mymensingh, Bangladesh
Md. Solaiman Ali Fakir
Department of Crop Botany, Bangladesh Agricultural University, Mymensingh, Bangladesh
A.K.M.Azad-ud-doula Prodhan
Department of Crop Botany, Bangladesh Agricultural University, Mymensingh, Bangladesh
Mohd. Razi Ismail
nstitute of Tropical Agriculture, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
M. Ashrafuzzaman
nstitute of Tropical Agriculture, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia
Mungbean, Raceme, Nodal position effect, Pod retention, Xylem and phloem
Field Laboratory, Bangladesh Agricultural University (BAU), Mymensingh
Crop-Soil-Water Management
Site description - Two experiments were carried out at the Field Laboratory of Bangladesh Agricultural University (BAU), Mymensingh (24.80 N 90.50 E), Bangladesh, during Kharif-I season (February-May) of 2009 and 2010. The soil of the experimental area of BAU is silty loam having a total nitrogen 0.06%, organic matter 1.15%, available phosphorus 18.5 ppm, exchangeable potassium 0.28 meq%, sulphur 18 ppm and pH 6.8. Planting materials and experimental design - Four genotypes (Two high and two low yielding) were considered in the study. Two high yielding genotypes were BMX 942-8 and VC 6173, and two low yielding genotypes were MB 300 and VC 3960. Seeds were sown on 22 and 18 February for the year 2009 and 2010, respectively. Seeds were sown in line having row to row distance was 30 cm and plant to plant distance was 10 cm. A randomized complete block design with 3 replications was followed and unit plot size was 1.5 m × 1.5 m. Management practices - Seeds were sown continuously in line and two weeks after germination, the plants were thinned to a density of 30 plants/m2. Cultural practices were the same in both the seasons. Uniform plant stands (30 plants m-2) were maintained in both the seasons. Urea, triple superphosphate, muriate of potash and gypsum were used as a source of nitrogen, phosphorus, potassium and sulphur at the rate of 40, 120, 80 and 30 kg ha-1, respectively at the time of final land preparation. First weeding was done followed by thinning at about 21 days after sowing (DAS) and second weeding was done at 40 DAS. A single irrigation was given at 25 DAS at both the seasons. Insecticide (Ripcord 50 EC at 0.025%) was sprayed twice (50 and 60 DAS) at flowering and fruiting stage to control shoot and fruit borer. Parameters measured - For investigation of the pattern of podset within raceme, 50 undamaged racemes plot-1 were collected from each genotype. Racemes were collected from the upper three nodes of the mainstem and were considered for studying yield components and pod growth within raceme. Pods were harvested node wise in the raceme and pooled, and finally, the number of pod set node-1, number of seeds pod-1 and pod size were recorded on individual node. For growth study of earlier- and later-formed pods in the raceme, all opened flowers were tagged at the two nodal positions, proximal 1-3 nodes and distal 4-6 nodes separately during flower opening so that the age of pods can be determined. Pods were harvested at 2 days interval from opening up to maturity. Each sample consisted of three replicates and a replicate had 10 pods. Samples were oven dried to a constant weight at 80 ± 2 0C for 48 hours and the dry weights of seeds and pericarps were recorded. Finally, pod growth rate (PGR) at 4 days interval until maturity was calculated separately for two positions in the raceme. For anatomical investigation of rachis of the raceme, two genotypes were considered in the experiment viz., BMX 942-8 (high yielding) and MB 300 (low yielding). The raceme samples were collected from upper part of the mainstem. Normally individual raceme consists of 16-30 nodes and flowering begins from the basal node and proceeds acropetally i.e. flowering proceeds from base towards top in the rachis, and each raceme takes about a week for flower opening is called first flush (1-5 nodes). Following first flushes, further flowering do not occur until pod growth of first flush completes within 14-16 days after flowering begins. After physiological maturity of pods from first flush, flower opening begins again at the distal end (11- 15 nodes) of the same raceme, which is termed as second flush (11-15 nodes) and the duration of flowering in the second flush is only about 2-4 days. In the present investigation, free hand sectioning of rachis in the two positions, 1-5 nodes where pods were set and from 6-14 nodes where no pod was set in the first flush of the raceme was considered. Before sectioning, the length and diameter of pod bearing rachis was recorded using a ruler and slide calipers, respectively. Hand sectioning of fresh material was done by sharp stainless razor blades within four hours after sample collection. Following cutting, the sections were stained with Safranin dye and were examined under the compound microscope immediately after slide preparation. The radial length of vascular tissue, xylem and phloem, was measured separately using a micrometer set at the eyepiece. The radial length of vascular tissue, xylem and phloem, was measured at the proximal (1-5 nodes) and distal part (6-15 nodes) of the rachis. Statistical analysis - All data were analyzed statistically as per the used design following the analysis of variance (ANOVA) technique and the mean differences were adjusted with Duncan’s Multiple Range Test (DMRT) using the statistical computer package program, MSTAT-C. The parameters of rachis diameter, xylem, phloem and vascular tissue were analyzed as design of two factor
completely randomized design year wise. Node wise yield attributes and seed yield of rachis were analyzed as one factor randomized complete block design year wise. Microsoft Excel was used for graphical presentation.
AJCS 5(13):1685-1691 (2011); ISSN:1835-2707
Journal