Wheat Research Centre, Bangladesh Agriculture Research Institute. Joydebpur. Gazipur, Bangladesh
Craig A. Meisnert
CIMMYT, Uttara, Bangladesh
Wheat sterility has occurred in some years in growers' fields in the north-west of Bangladesh, causing devastating yield reductions. An experiment was organised to understand the reasons for sterility in wheat in Bangladesh. It was conducted during the 1994-95 wheat-growing season at the Wheat Research Centre, Dinajpur. Three genotypes of varying degrees of sterility associated with boron deficiency were sown at three planting dates to vary the growing environment. Seeding dates, genotypes and their interactions significantly influenced the dates and timing of phenological events (such as days to heading and anthesis). There was no significant influence of boron on sterility or basal floret fertility. Sterility varied only with genotypes; interactions with boron and seeding date were not significant. Significant differences were observed between genotypes, seeding dates and their interaction on yields and on most variables that contribute to yield. Boron concentrations in the flag leaf at booting were highly correlated with soil-applied boron.
Wheat, Sterility, Bangladesh:
Wheat Research Centre, Dinajpur.
This paper briefly reports the findings of the experiment conducted in Bangladesh, especially focusing on the interactions and correlations between the sowing dates, boron levels and genotypes and their effects on wheat sterility.
The experiment was conducted in an experimental field of the Wheat Research Centre, Dinajpur, during the 1994-95 wheat-growing season. The experimental site Bes at 25°38'N latitude and 88° 41 'E longitude at an altitude of 38 m. The soil is a sandy loam with a low pH (5.7) and belowcritical levels of organic matter, nitrogen and boron (Saifuzzaman, unpublished data). The three-factor factorial experiment was arranged in a split-plot design and replicated four times. Plot size was 3 m x 3 m. Seed was sown by hand in rows 20 cm apart. Main plots received B at 0 or 1 kglba as borax (11 % B). The sowing times were 20 November,S December and 20 December 1994. This increased the chances of crops being exposed to varying environmental growing conditions. Previous data and observations had indicated that foggy weather (high humidity) with low temperatures at some critical growth stage disposes wheat to sterility (Saifuzzaman, unpublished data). Three wheat genotypes were used in the subplots, representing varying degrees of susceptibility to boron deficiency and associated sterility: Fang 60 (Iow susceptibility), Kanchan (medium susceptibility) and SW 41 (high susceptibility). The seed was treated with Vitavax'" 200 and sown at the rate of 120 kglba. N, p. K. Sand Zn fertilizers were applied as urea (120 kglba), triple superphosphate (60 kglba), potassium chloride (40 kg/ha), gypsum (20 kg/ha) and zinc oxide (4 kglba). The urea was applied as two-thirds basal and one-third top-dressed at growth stage 20 of Zadoks et at. (1974). One irrigation was given immediately after sowing for better plant emergence. Three further irrigations were applied at stages 20, 50 and 70 of Zadoks et at. The site was weeded manually at 25 days after sowing. Twenty to thirty flag leaves and young spikes were collected randomly, dried at 80'C for 72 hours and then shipped to Chiang Mai, where they were analysed for boron content following standard methods (AOAC 1984).
Sterility in Wheat in Subtropical Asia: extent, causes and solutions, Proceedings of a workshop 18-21 September 1995
LumJe Agricultural Research Centre, Pokhara, Nepal
Many years of research in many countries in South and Southeast Asia have eliminated single factors as the main causes of wheat sterility in growers' fields. Low soil boron concentrations were thought to be the main factor, though data in Bangladesh do not support the hypothesis. Genotypic differences are obvious, but more work is needed to assess and understand them. In Bangladesh, low light caused by foggy weather under low temperatures for several days before or during flowering under low soil boron conditions is the probable cause of sterility in growers' fields. Prevention of sterility by better crop management is possible by increasing the soil OM levels, which improve the soil structure for better rooting as well as increasing nutrient availability and reducing the risk of waterlogging.