Assessment of diversity on corn (Zea mays L.) germplasm using morphological markers.

Date

6-2012

Degree

Bachelor of Science in Agriculture

Major Course

Major in Agronomy

College

College of Arts and Sciences (CAS)

Abstract

The study aimed to characterize 50 accessions of corn conserved at the NPGRL using morphological markers, determine the extent of variation in the collection and possibly identify some elite accessions for direct utilization as varieties for planting or as parental in varietal improvement program. The extent of diversity of the 50 accessions used in the study at NPGRL was analyzed, using Shannon-Weaver (H’) diversity analysis. Results showed that the quantitative traits have a high mean diversity index (0.75), while the qualitative traits have a moderate mean diversity (0.45). The overall mean diversity index is 0.64. The high mean diversity index in quantitative traits show that there are many possible good candidates to be used as parental in varietal in improvement of quantitatively-inherited characters like plant height, ear length, ear diameter, number of kernel rows, number of kernels per row and 1000 seed weight. Meanwhile, the moderate mean diversity index exhibited in qualitative characters of corn would mean that there are still enough sources of genes for improvement of qualitative plant characters like husk cover, ear shape, kernel type, and ear tip shape. The moderate mean diversity index for the qualitative traits, could be related to the narrow genetic base as these traits are least affected by the environment. The overall diversity of the 50 accessions is moderate, many of the accessions have similar qualitative characters thus lowering the overall mean diversity index, but there are still enough accessions that could be used in a varietal improvement program. Clustering the 50 corn accessions based on qualitative characters generated six clusters at coefficient 0.63 and by combining both qualitative and quantitative characters using Gower’s coefficient six clusters are generated at Gower’s coefficient 0.20. There is a need to further characterize and evaluate the rest of the corn collection conserved at NPGRL. Biochemical and molecular characterizations are recommended to determine the extent of diversity of corn collection and to fill the gaps of other characters not yet found in the Philippines. These techniques can also eliminate the effect of the environment that is present in the morphological characterization especially quantitative characters. Hence, high accuracy and consistency can be obtained in using it. It is also important to know what accessions are resistant to pests and diseases since in a varietal improvement program both yield and pest and disease resistance are simultaneously improved because of their negative correlation.

Language

English

Call Number

LG 993.5 2012 A42 R36

Document Type

Thesis

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