Identification of Germplasm of Possible Value for Confronting an Unfavorable Inverse Genetic Correlation in Tobacco
To be commercially viable in the USA, a flue-cured tobacco (Nicotiana tabacum L.) cultivar must be high-yielding and also meet minimum requirements for percent total alkaloids (PTA). The negative correlation between yield and PTA complicates development of higher-yielding cultivars with acceptable leaf chemistry, however. Identification and use of germplasm possessing alternative alleles positively affecting PTA could be an important component of strategies to develop commercially acceptable, higher-yielding cultivars. Choice of donor germplasm should be done carefully, however, because yield modulates the phenotypic expression of PTA. Consequently, comparison of materials for genetic potential to accumulate alkaloids might best be done at common levels of yield. This investigation used manual control of leaf number to manipulate yield of fifteen diverse tobacco genotypes grown in a split-plot design in two North Carolina environments. Within genotypes, the relationships between PTA and yield were found to be negative. Through statistical analyses, germplasm accessions TI 464 and TI 959 were found to exhibit the highest levels of PTA at given levels of yield in both environments. Data on N-partitioning indicated that these genotypes may have increased genetic potential for utilizing accumulated N for alkaloid synthesis. Transfer of alleles from these genotypes to elite germplasm pools may facilitate development of higher-yielding cultivars with acceptable PTA levels.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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