Full Length Research Paper

Estimation of fruit weight by cane traits for eight American blackberries (Rubus fructicosus L.) cultivars

S. Peral Eyduran¹*, Ecevit Eyduran² and Y. Sabit Agaoglu³

¹Department of Horticulture, Ozalp Vocational High School, University of Yuzuncu Yil, Ozalp, Van, Turkey.

²Department of Animal science, Faculty of Agriculture, Yuzuncu yil University, 65080, Van, Turkey.

³Department of Horticulture, Faculty of Agriculture, University of Ankara, 06110, Diskapi, Ankara, Turkey.

*Corresponding author. E-mail: peralatilla@gmail.com. Tel: 0090 4322251024/2693. Fax: 0090 312 3182666.

Accepted 2 July, 2008

The present paper aimed to estimate fruit weight by their cane traits (the number of cane, cane height, cane diameter, and cane yield) for eight American blackberry cultivars (namely, Ness, Cherokee, Arapaho, Chester Thornless, Navaho, Black Satin, Dirksen Thornless and Cv. Jumbo) grown in Central Anatolia during 2002 - 2006. For this aim, average of fruit weight (dependent variable) for each cultivar was estimated by independent variables such as the number of cane, cane height, cane diameter, and cane yield in Multiple Regression Analysis (MRA). With respect to determination coefficients for each cultivar, it is clear that cultivars having the best fit (giving the best R² values) in MRA were found to be Black Satin (99.40%), Ness (99.16%), Navaho (96.46%), Dirksen Thornless (96.22%), Chester Thornless (91.92%), and Cv. Jumbo (91.26%), which meant that most (almost 100%) variation in fruit weight for these cultivars was explained by the number of cane, cane height, cane diameter, and cane yield. However, corresponding values for Arapaho and Cherokee cultivars was estimated as 2.88% and 33.2% of the total variation in fruit weight. It was concluded that number of canes had positive-significant effect on fruit weights of Dirksen Thornless (P < 0.001) and Cv. Jumbo (P<0.01), but negative-significant effect on that of Black Satin (P < 0.001). Cane height had positive-significant effect on fruit weights of Black Satin (P < 0.001) and Ness (P<0.001) cultivars, but negative-significant effect on cv. Chester Thornless (P < 0.001) and Dirksen Thornless (P < 0.01). Cane diameter had positive-significant effect on fruit weights of Black Satin (P < 0.001) and Chester Thornless (P < 0.01), Navaho (P < 0.05), Ness (P < 0.01) cultivars, whereas it had negative-significant effect on cv. Jumbo (P < 0.05). Cane yield had positive-significant effect on fruit weight of only Cv. Jumbo, but negative-significant effect on cv. Black Satin (P < 0.001), Chester Thornless (P < 0.01), Dirksen Thornless (P < 0.001), Navaho (P < 0.001) and Ness (P < 0.001). It was concluded that cane traits with the positive and negative effect on fruit weight provide useful clues for breeding proposes to improve fruit weight.   

Key words: Blackberry, cane traits, fruit weight estimation, multiple regression analysis.