Quantitative genetic parameters of agronomic and quality traits in a global germplasm collection reveal excellent breeding perspectives for Jatropha curcas L.

Abstract

Jatropha curcas L. (jatropha) is an undomesticated plant, which has received great attention in recent years for its potential in biofuel production and in greening and rehabilitation of wastelands. Yet the absence of improved cultivars and the lack of agronomic knowledge are limiting factors for successful jatropha cultivation. The objectives of the present study were to investigate the perspectives of a worldwide jatropha breeding program and specifically to (i) estimate variance components and heritabilities for agronomic and quality traits in the early phase of cultivation; (ii) assess phenotypic and genetic correlations among those traits; and (iii) discuss strategies for breeding high yielding jatropha cultivars. Data on various traits was collected from 375 jatropha genotypes, which were tested at seven locations during the first 3 years of growth. The accumulated seed yields and the seed yields per harvest year differed significantly among the testing locations. The estimates of genetic and genotype-by-environment interaction variances were significant and estimates of heritabilities were high for all yield parameters. The estimates of genetic correlations indicated a strong association among yield parameters. Oil yield was strongly correlated with seed yield and only weakly with oil content in seeds. The perspectives of a jatropha breeding program are excellent. Improved cultivars, definition of favorable environmental factors and refinement of agronomic management practices are needed to secure sustainable jatropha cultivation.

Effects of Genotype, Direct Sowing and Plant Spacing on Field Performance of Jatropha curcas L.

“…On the other hand, oil content in seeds harvested at the dry-subhumid site (42.6% in the set of common genotypes) was significantly higher than that in seeds at the humid site (35.2% in the set of common genotypes). Previous studies indicated a strong influence of the environment on seed yields and oil content [7] and a relation of higher protein content in seeds harvested in humid environments to increased nitrogen uptake due to better water availability [19]. The results of the present study further underpin the need for further research on the environmental factors that determine seed and oil yield in jatropha.…”

“…Canopy management is an important aspect in older jatropha stands, which can be addressed by partial plant elimination and/or pruning [4,20], depending on agro-ecological conditions and plant architecture. Pruning, however, can lead to plant stress and therefore to a reduction of productivity [7,21]. In the long run, varieties with reduced plant height or canopy diameter will be developed that should facilitate harvesting and canopy management practices.…”

“…Successful cultivation of jatropha requires understanding of agronomic management from the early stage to its yielding phase. Its agronomic performance depends on the genotype, the environmental conditions, and the interaction between these two factors [7]. Multi environmental testing conditions are needed to assess the effects of these three factors in order to select the best performing cultivars [8].…”

Quantitative Trait Variation in Self- and Cross-Fertilized Seeds of Jatropha curcas L.: Parental Effects of Genotypes and Genetic Pools

“…Despite the large variation for oil content, the oil yield per hectare is not well associated with that trait [11]. Therefore, selection for oil content at early stages of a jatropha breeding program does not correspond with high oil yield per hectare.…”

“…Therefore, selection for oil content at early stages of a jatropha breeding program does not correspond with high oil yield per hectare. Selection for seed yield and stability has been indicated to achieve rapid and large selection gains [11]. Improvement of oil content could be achieved by recurrent selection cycles within genetic pools and also by inter-pool hybridization.…”