Drought tolerance screening of seven salt-tolerant varieties of tomato (Solanum lycopersicum L.) using physical and physiological characterization and gene expression analysis.

Date

4-2010

Degree

Bachelor of Science in Biology

Major Course

Major in Ecology Genetics

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Cheryl A. Agdaca

Abstract

Seven salt-tolerant tomato varieties, namely LA1606, LA1310, LA00175, LA1421, LA2079, LA2081, and LA4133 were screened for drought tolerance by physical and physiological characterization and gene expression of NHXI, AVPI, CHIT, TASI4, 1'11'1 and P1P2. The drought-sensitive (CA4) and drought-tolerant (LA1579) varieties were also included in the screening for comparison. Tomato plants used were at the flowering stage. For the physical and physiological characterization, significant (p<0.05) variety by water treatment interaction effect was observed only in plant height and root dry weight. Significant main variety effect was observed in all parameters except chlorophyll fluorescence while there was significant water treatment effect in all parameters except root length and root-to-shoot ratio. However, there was no significant trend evident for transpiration efficiency. Generally, all the salt-tolerant varieties performed well under drought stress but only LA1606 and LA2079 were analyzed for gene expression since these two were the best performing lines under salt-stress. Gene expression was analyzed by comparing the mean fold change in expression relative to CA4 well-watered treatment (WW1) computed from the cycle threshold (CT) values generated by RT-PCR using the 2'5' method. Among the six molecular markers used, significant overexpression was observed for NHX1, AVPI, CHIT and 7:4S14 in LAI606 and LA2079 subjected to drought stress but not in PIP I and PIP2. Thus, it is highly probable that genes encoding these four proteins play a role in drought tolerance of tomatoes during the flowering stage. Salt-tolerant genotypes could be a potential source of these genes.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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