Marker-based analysis of genetic diversity and its relationship with heterosis in doubled haploid rice (Oryza sativa L.)

Date

4-2014

Degree

Bachelor of Science in Biology

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Merlyn S. Mendioro

Abstract

While there is lack of systematic study in heterotic groups in rice which is important in identifying genetically diverse parents for maximum exploitation of heterosis, there is still no clear relationship between parental genetic diversity and heterosis in rice. In this study, 27 doubled haploid 9DH) lines, from populations AC 11 (PJ23 x IR34686R, japonica x indica) and AC 57 (PR36847-3R x IR346869, indica x indica), were crossed with three widely used cytoplasmic male sterile 9CMS) testers using LxT mating design for agronomic evaluation. The materials were genotyped using genomewide SSR markers (6Mb bin system) for genetic diversity analysis. The parental genetic diversity and midparent heterosis of the crosses were then correlated. The close range of genetic distances between DH line and CMS testers was explained by the lineage similarity of the three testers, which in turn validated the high contribution of DH lines and interaction of DH lines x CMS testers to the diversity observed in the crosses. Three top crosses with high specific combining ability (SCA) estimates and superior heterotic effects were identified these were IR58025A x AC 11-6-3 (5941.87, 51.84%), IR58025A x AC 11-2-3 (5396.87, 45.76%), abnd IR68897A x AC 57-2-5 (5271.47, 40.27%). Number of tillers, grains per panicle and grain yield, which were significant for DH lines x CMS testers interaction, were the only traits which have heterosis of over 10%. Correlation analysis revealed significant negative relationship between genetic diversity and heterosis for plant height (R2=0.34), number of tillers (R2=0.27), and grain yield (R2=0.30) while it was positive for panicle length (R2=0.50), 1000 grain weight (R2=0.41), and fertility (R2=0.20). This study proves the effectiveness of genetic diversity as a tool in exploting maximum heterosis despite the lack of direct correlation between these factors.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

LG 993.5 2014 B4 /L53

Notes

Major in Genetics

Document Type

Thesis

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