SCREENING OF ALLELOPATHIC POTENTIAL BANGLADESH WHEAT (Triticum aestivum L.) VARIETIES

Abstract

A series of experiments were carried out in the laboratory and agronomy field of the Sher-e-Bangla Agricultural University, Dhaka, Bangladesh, from September 2018 to March 2019 to screen out the allelopathic potential Bangladesh wheat varieties (Triticum aestivum L.). The experimental design in laboratory bioassay was a completely randomized design (CRD) with four replications and a randomized complete block design (RCBD) with three replications in the field experiment. Initially, the donor-receiver bioassay method was used to assess allelopathic potential varieties in laboratory (in-vitro) conditions. Raphanus sativus (radish) and Lactuca sativa (lettuce) as model receiver plants, Chenopodium album (common lambs’ quarter), and Amaranthus viridis (pigweed) as test receiver weeds were used for the screening test. BARI Gom 21 gave the highest inhibition effect (81%) on C. album root while the stimulating effect was given by BARI Gom 30 (-48.2%) on R. sativus root. BARI Gom 21 also reduced the speed of germination against R. sativus, L. sativa, C. album, and A. viridis (5.35, 4, 4.32 and 5.83 respectively) as well as the coefficient of the velocity of germination of A. viridis was 1.92. Eleven wheat varieties were selected including allelopathic and non-allelopathic from the laboratory test for the field study which was raised by following no weed control method. The growth pattern of infesting major weeds concerning wheat grown for grain in wheat fields was also observed. There were different weed species under nine different flora families viz., Cynodon dactylon, Eleusine indica, Echinochloa colona, Cyperus rotundus, C. album, A. viridis, A. spinosus, Heliotropium indicum, Alternanthera philoxeroides, Corchorus acutangulus, Vicia sativa, Solanum caroliensis, S. torvum, Lindernia procumbens, etc. which infested experimental plots. BARI Gom 21 raised plots had the lowest infestation and the lowest dry matter of weeds (12 g) resulting in maximum weed control efficiency (87%). In addition, several weed species including C. album and A. viridis were not grown in the BARI Gom 21 variety raised plots. The strong allelopathic inhibition of this variety on the seed germination and seedling growth of wheat may be the important reason for these weeds' repulsion in the wheat field. BARI Gom 21 reduced the weed density (14.66 m -2 , 28.33 m -2 and 33.33 m at 15, 25 and 35 DAS respectively). The Simpson Diversity Index (SDI) was calculated against different varieties, and the highest in BARI Gom 21 (0.82) and the lowest in BARI Gom 22 (0.68). There found a positive correlation (R 2 = 0.386) between SDI and the root inhibition percentage of laboratory bioassay. Therefore, BARI Gom 21 wheat variety was selected as the most allelopathic among the tested Bangladesh wheat variety. This wheat variety could be used for the isolation and identification of allelochemicals and to develop by breeding and adopting other agronomic practices for obtaining optimum yield performance and tolerance to weeds, and in particular, to achieve improved biological weed control for the sustainable production of wheat.