Optimal Methods for Estimating Cactus Pear Biomass Using Cladode Dimensions of Morphologically Diverse Accessions

Area of Science:

• Agricultural Science
• Botany
• Plant Physiology

Background:

• Current allometric methods for estimating cactus pear (Opuntia spp.) biomass are insufficient for field applications with diverse plant accessions.
• Refinement of these methods is crucial for accurate, non-destructive biomass assessment in varied agricultural and ecological settings.

Purpose of the Study:

• To develop and validate improved allometric models for estimating cladode fresh weight in morphologically diverse cactus pear accessions.
• To compare the performance of different modeling approaches, including Box, Fitting-box, and Elliptical models, for predicting biomass.

Main Methods:

• Analysis of cladode dimensional data from 14 accessions (four species and two hybrids) of Opuntia spp.
• Development of cross-accession models using factorial combinations of cladode dimensions (length, width, thickness, diameter) to estimate fresh weight.
• Utilized ImageJ for area measurement and developed Elliptical and Fitting-box models for comparison.

Main Results:

• A Box model incorporating multiple dimensions achieved the highest general fit (R² = 0.95) for estimating fresh weight across all accessions.
• The Elliptical model provided a strong general fit (R² = 0.94) while simplifying measurements.
• Fitting-box models using ImageJ-derived area also showed good performance (R² = 0.93).

Conclusions:

• The developed Box, Fitting-box, and Elliptical models offer efficient and accurate tools for non-destructive estimation of cactus pear biomass.
• These refined models outperform previous methods when applied to morphologically diverse cactus pear accessions in field conditions.
• The study provides valuable methodologies for agricultural and ecological research involving Opuntia spp. biomass assessment.