Document Type : Research Paper

Authors

• Zahra Qalebi ¹
• Mohammad Modarresi ²
• Fariba Sohrabi ³
• Dariush Saberi ⁴
• Mohammad Hedayat ⁵

¹ M.Sc. Graduate of Genetics and Plant Breeding, Department of Plant Genetics and Production Engineering, Faculty of Agriculture and Natural Resources, Persian Gulf University, Bushehr, Iran

² Assistant Professor, Department of Plant Genetics and Production Engineering, Faculty of Agriculture and Natural Resources, Persian Gulf University, Bushehr, Iran

³ Associate Professor, Department of Plant Protection, Faculty of Agriculture and Natural Resources, Persian Gulf University, Bushehr, Iran

⁴ Associate Professor, Department of Marine Chemistry, Faculty of Marine Sciences and Technology, Persian Gulf University, Bushehr, Iran

⁵ Assistant Professor, Department of Horticultural Sciences, Faculty of Agriculture and Natural Resources, Persian Gulf University, Bushehr, Iran

Abstract

 
Abstract
Introduction
Pests and their controlling pesticides are among the most serious threats to the health of agricultural products. The present study was aimed to investigate the effect of variety and the possibility of replacing chemical pesticides controlling fruit borer with some compounds of natural origin for plant traits improvement and damage reduction of tomato fruit borer. Factorial experiment was done in the template of randomized complete block design with three repetitions.
 
Materials and Methods
Factors included 9 levels of pest control compounds and 5 varieties (PA-136, PA-162, PA-135, PA-688 and PA-483). Compounds involved Salicylic acid (5 and 15 mM), Jasmonic acid (50 and 100 μM), two pesticides, Abamectin (750 and 1500 mg/L), Chlorpyrifos (1250 and 2500 mg/L) and control. Measured traits involved morphological traits (fruit yield, fruit weigh, numbers of fruit per cluster, plant height and chlorophyll index), phonological traits (days to flowering and days to physiological maturation), phytochemical traits (TA, TSS, and ascorbic acid (Vitamin C)) and relative properties to evaluating resistance to fruit borer (the percentage of leaf and fruit damage).
 
Results and Discussion
Significant variation was observed between varieties. The maximum fruit yield per plant was related to PA-136 variety with applications of two-levels of Chlorpyrifos and Jasmonic acid, PA-162 variety with application of first level of Abamactin, second level of Salicylic acid and PA-135 and PA-688 varieties with the second level of Chlorpyrifos. The highest significant positive correlation with yield related to single fruit weight (r=0.48^**) and the highest significant negative correlation were related to days to flowering (r= -0.52^**). In stepwise regression analysis of single plant yield as a dependent variable, three traits including days to flowering, single fruit weight, and a percentage of pest damage on leaf (as the most important traits) were incorporated in the regression model that totally explained 49% of variations. Path analysis results indicated that the highest positive direct effect (0.42) was related to single fruit weight, and the highest indirect effects (-0.047) had to do with this trait via days to flowering. The first four components were chosen in principal component analysis, explaining totally 62.5% of phenotypes variation.
 
Conclusion
Reducing pest damage on leaf and fruit in applying Salicylic acid and Jasmonic acid is suitable and resulted in the same level of chemical control use.Thus, findings may be used in the design of breeding programs for plant trait improvement and integrated pest management of tomato fruit borer.

Keywords

• Genetic diversity
• Path analysis
• Principal component analysis
• Plant traits improvement
• Stepwise regression

Main Subjects

• B: Plant Breeding