Allometric relationships and growth indices analysis in aerobic, upland, and lowland rice (Oryza sativa L.) genotypes

An experiment with following objectives a) investigation of allometric relations between plant height and vegetative organs dry weight with leaf area, b) parameterization and allometric coefficient determination, c) leaf area and dry mater estimation and aerobic , and d) comparison of genotypes in aspect of this parameters was done in the University of Guilan in 2016. The experiment was included three cultivation condition (lowland, aerobic, and upland) and five selected genotypes (3 aerobic, 1 upland, and 1 lowland) in three replications as RCBD. Data of leaf area, dry weight of vegetative organs, and plant height were recorded each 10 days. For description of leaf area index (LAI) and dry mater two separate beta models and for allometric relationship between leaf area and plant height and vegetative organs dry weight, a segmented model were fitted. Result showed that the segmented regression model can be used for leaf area estimation from plant height and vegetative organs dry weight in rice (considering to stable allometric relationship in three cultivation system and five genotypes and low RMSE and high and significant R2). Time to maximum LAI (Tm) in lowland conditions was longer than aerobic conditions and growth rate in linear phase (cm) in lowland more than aerobic. IR 80508-B-194-4-B (AR6) as an aerobic line in aspect of phonotypical characteristics was better than other genotypes and near to ideotype. This genotype has LAI in three cultivation system in aerobic condition. Also this genotype has the lowest dry mater losses in aerobic and water stress conditions, the highest cm, and high primary establishment vigor based on allometric coefficient. Therefore, allometric coefficient resulted in this paper can be used in rice crop modelling and presented line can be used in breeding programs and other supplementary experiment.