Effects of reduced irradiance on leaf morphology, photosynthetic capacity, and fruit yield in olive (Olea europaea L.)

The evergreen tree olive (Olea europaea L.) is the only species of the genus Olea that produces edible fruits with high ecological and economic value. This tree species has developed a series of physiochemical mechanisms to tolerate drought stress and grow under adverse climatic environments. One of these mechanisms is photosynthesis activities, so that as yet little information achieved about the relations between olive production and photosynthetic parameters under drought conditions. An experiment was carried out during two consecutive years (2015–2017) to study the response of 20 different olive tree cultivars (Olea europaea L.) to drought stress. Several parameters like net photosynthetic rate (PN), stomatal conductance (GS), transpiration rate (TE), photosynthetic pigments (total chlorophyll, chlorophyll a, b and carotenoid) and fruit yield were measured. The results of combined analysis of variance for fruit yield and other measured traits showed that year, drought treatment, cultivar main effects and their interactions were highly significant. The results indicated that drought stress reduced all traits, however GS (42.80%), PN (37.21%) and TE (37.17%) significantly affected by drought. Lower reduction in photosynthetic performance (PN, GS and TE) in the cultivar T7 compared to other olive cultivars allowed them to maintain better fruit yield. Principal component analysis (PCA) identified two PCs that accounted for 82.04 and 83.27% of the total variation in photosynthetic parameters under optimal and drought stress conditions, respectively. Taken together, mean comparison, relative changes due to drought and biplot analysis revealed that cultivars ‘T7’, ‘Roghani’, ‘Koroneiki’, ‘Korfolia’ and ‘Abou-satl’ displayed better response against drought stress. According to our results, one olive cultivar namely ‘T7’, could be used in olive breeding programs to improve new high yielding cultivars with drought tolerance for use in the drought-prone environments.

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Genetic diversity and character association analysis based on pomological traits in olive (Olea europaea L.)

Journal of Applied and Natural Science ◽

10.31018/jans.v9i3.1400 ◽

2017 ◽

Vol 9 (3) ◽

pp. 1551-1556

Author(s):

S. Lal ◽

O. C. Sharma ◽

D. B. Singh

Keyword(s):

Olea Europaea ◽

Oil Content ◽

Positive Association ◽

Fruit Weight ◽

Fruit Yield ◽

Path Coefficient ◽

Path Coefficient Analysis ◽

Significant Positive Association ◽

Olea Europaea L ◽

Olea Europaéa

Thirteen exotic genotypes of olive (Olea europaea L.) were studied for the genetic variability, correlation and path coefficient analysis for fruit quality, yield and yield contributing traits at experimental farm of ICAR-CITH, Srinagar during 2009-2013. Maximum variability was recorded for fruit yield and oil content, however, low differ-ences between the phenotypic and genotypic coefficients of variations indicated low environmental influences on the expression of these characters. High heritability coupled with high genetic advance was obtained with fruit yield per plant, acidity, fruit pulp weight, fruit weight and stone weight. Fruit weight (r=0.329), stone weight (r=0.405) and oil content (r=0.841) were the most important traits, which possessed significant positive association with fruit yield per plant. Path coefficient analysis revealed that among the different yield contributing characters oil content (0.875), fruit weight (0.797) followed by acidity (0.501), peroxides value ( 0.199) and fruit length (0.054) influenced fruit yield per plant directly. The direct effects of these characters on fruit yield were found positive and considerably very high.The selection based on fruit weight, stone weight oil content and yield per plant will be effective for enhancing the fruit and oil yieldand making future olive breeding strategies.

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