High temperature stress during grain-filling period is one of the major environmental constraints limiting the grain yield of wheat in Bangladesh. Crop growth response and relative performance of yield components of ten wheat genotypes were studied in two temperature conditions in glass rooms in a Phytotron to identify the genotype tolerant to high temperature stress. A favourable day/night temperatures of 15/10, 20/15, and 25/20 0 C were maintained from sowing to 60 days after sowing (DAS), 61 to 80 DAS and 81 DAS to maturity, respectively, in one glass room (G 1 ); whereas day/night temperatures in another glass room (G 2 ) was always maintained at 5°C higher than that of G 1 . Green leaf area and number of tillers in different times, number of days for the occurrence of major crop growth stages, relative performance in yield components, grain yield and heat susceptibility index were estimated following the standard methods. The higher temperature enhanced plant growth, flowering, and maturation. Thus the number of days to booting, heading, anthesis, and maturity of wheat were significantly decreased that varied among the genotypes. Green leaf area and productive tillers/plant were drastically reduced in time under high temperature. The reduced number of grains/spike and smaller grain size resulted from drastic reduction in growth duration were responsible for the yield loss of wheat at high temperature. Out of ten wheat genotypes, three were characterized as high temperature tolerant based on their relative performance in yield components, grain yield and heat susceptibility index.

The aim of this study was to isolate superior inbred lines and better combining parents for suitable hybrids and to determine percent of heterosis using standard commercial checks in a 7 × 7 diallel analysis excluding reciprocals over five environments. The mean sum of square obtained from combined analysis of variance showed the presence of genetic variability among the crosses, environment and crosses × environment interaction for all of the characters under study. The variances for general combining ability (GCA) and specific combining ability (SCA) of variance were found significant for all the characters. However, relative magnitude of variances indicated that additive gene effects were more prominent for all the characters studied. GCA and SCA effects both showed significant interaction with environment for all the traits. This clearly suggested the need of selecting different parental lines for hybrids for different ecological situations. Parents P3, P5 and P6 were the best general combiner for high yield; parents P6 for earliness; and P1, P2 and P3 for dwarf plant type. The range of heterosis expressed by different crosses was from -13.04 to 5.25 % percent for grain yield. The better performing six crosses (P1 × P2, P1 × P5, P3 × P4, P3 × P6, P3 × P7 and P4 × P5) can be utilized for developing high yielding hybrid varieties as well as for exploiting hybrid vigour. These crosses also need to be evaluated further in multilocations.

A field experiment was conducted at the Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, Bangladesh during winter season, 2007 -2008 to determine the effects of N and B on the yield and hollow stem disorder of broccoli. Four levels of N as 0, 60, 120, 180 kg ha -1 and four levels of B as 0, 0.5, 1.0 and 1.5 kg ha -1 constituting sixteen treatments were applied in a split plot design with three replications. Applied N and B had significant impact on the yield and hollow stem disorder of broccoli. The highest curd yield of 15.14 t ha -1 was obtained by 180 kg N ha -1 . The incidence of hollow stem disorder was increased by increasing rate of N application and the highest value of hollow stem index of 1.38 was found with 180 kg N ha , which might be recommended for farmer's practice in the Shallow-Red-Brown Terrace Soil of Madhupur Tract.

93 cm), the maximum percentage of spikes (88.1%), and corm (97.6%), the heaviest and the largest corm (19.5 g and 4.11 cm, respectively), cent percent flowering sized corm, and the highest corm number and cormel yield (1,20,000 and 1.66 t/ha, respectively). The corm produced from this treatment combination also showed better performances in the next year in respect of plant emergence (100%), florets/spike (13.1), spike and rachis length (82.2 cm and 45.4 cm, respectively), flower stick weight (57.1 g) and percentage of flower sticks (113%).

Fourteen genotypes of coriander (Coriandrum sativum L.) from diversed sources were evaluated at Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur during the rabi season of 2007 to 2008 to select the promising genotype (s) for higher seed yield. The genotype CS005 took the minimum days for bolting (38.00), while CS003 took the maximum (60.00 days) which developed 50% most early flowers (134.3 days) and the tallest plant (116.10 cm). The maximum number of primary and secondary branches were obtained from CS004 (8.70/plant) and CS001 (15.41/plant), respectively. Umbels/plant ranged from 12.70 (CS010) to 33.37 (CS003), while umbellates/ umbel ranged from 4.75 (CS003) to 6.67 (CS010). The maximum number of seeds were obtained from CS011 (35.63/umbel and 684.3/plant) and the lowest per umbel from CS005 (15.00) and per plant from CS010 (163.3). The highest fruit set was obtained from CS011 (48.20%) followed by that of CS007 (46.30%). The genotype CS002 had the maximum 1000-seed weight (12.00 g) and CS004 the minimum (1.65 g). The genotypes CS011 and CS007 gave the highest seed yield per plant (5.79 and 5.57g) as well as per hectare (1.34 and 1.05 t). The highest germination of seed was recorded in CS003 (84.4%) and the lowest in CS004 (67.96%). The genotypes CS004, CS005, CS010, CS013, and CS014 were attacked with stem gall disease. It might be concluded from the study that the genotypes differed significantly in most of the parameters and offer a good scope of selection of better genotypes for desired traits. Bangladesh J. Agril. Res. 38(2): 189-202, June 2013 DOI: http://dx.doi.org/10.3329/bjar.v38i2.15882