Morphological and grain characterısatıon of Macedonian weedy rice (Oryza satıva L.)

Abstract

Rice fields in the main rice producing region of the Republic of Macedonia sown with San Andrea and Onice cultivars were investigated with the aim to evaluate some morphological and grain characteristics of the present weedy rice types. Six morphotypes (two fully awned, three partly awned and one awnless) with pigmented pericarp were identified on the basis of the panicle morphology and grain characteristics. The plant height, panicle length, number of tillers and panicles per plant were examined on 30 plant samples of each type and compared to the cultivar. The grain and caryopsis dimensions were examined on 30 grains of each type. The weedy morphotypes isolated from Onice showed significantly higher plant height (from 102.47 cm to 113.47 cm) and panicle length (from 19.90 cm to 23.07 cm) in the field conditions compared to the cultivar (plant height: 79.50 cm; panicle length: 12.13 cm). In the San Andrea field, the weedy morphotypes had a significantly lower plant height values (from 106.17 cm to 108.63 cm) and non-significant to significantly longer panicle (18.10 cm to 20.50 cm) compared to the cultivar (plant height: 114.07 cm; panicle length: 17.24 cm). Significantly higher number of tillers and panicles per plant was determined in weedy rice compared to the rice cultivars. The weedy rice grain dimensions (length, width and thickness) were ranged from 8.30 to 8.85 mm, from 3.29 to 3.61 mm and from 2.03 to 2.22 mm, respectively, while the caryopsis dimensions varied from 6.15 to 6.62 mm, from 2.74 to 3.02 mm and from 1.82 to 2.04, respectively. The weedy rice morphotypes had significantly lower values for the three grain dimensions compared to San Andrea cultivar. Regarding the caryopsis, weedy rice had significantly lower values for two to three dimensions compared to San Andrea, depending on the morphotype. The differences in grain dimension between WR1323232 and Onice cultivar were non-significant. The rest of the weedy morphotypes exhibited significantly lower values for one to three grain dimensions in comparison to Onice. Depending on the weedy morphotype, significantly lower values for one to two caryopsis dimensions were found in comparison to Onice. Weedy rice had significantly lower 100 grains weight (from 2.84 to 3.28 g) compared to San Andrea (4.07 g) and Onice (3.56 g). Significant differences in the studied characteristics were also evident between the weedy accessions. On the basis of the results obtained in the current study can be concluded that different weedy rice morphotypes occur in the rice producing region of the Republic of Macedonia. The descriptive characteristics given in this study could be helpful in determining the presence of weedy rice in field conditions and in the harvested crop.