Morphological and cytogenetic studies in two strains of papaya (Carica papaya L.), 'MORADO' and 'SOLO', and their F1 hybrid

Date

4-2005

Degree

Bachelor of Science in Biology

Major Course

Major in Cell Biology

College

College of Arts and Sciences (CAS)

Adviser/Committee Chair

Celia B. Dela Viña

Co-adviser

Pablito M. Magdalita

Abstract

The morphology and cytogenetics of two strains of papaya (Carica papaya L.), 'Morado' and 'Solo', and their F, hybrid were studied. Morphological characterization was based on the descriptors for C. papaya provided by the International Board for Plant Genetic Resources. Using iron-acetocarmine squash technique, the chromosome number and behavior in meiosis I of the three populations were observed. Pollen fertility was estimated as the percentage of pollen grains that could be stained with iodine potassium iodide (121(1) solution. Morphologically, the stem diameter of the F, hybrid (28.8 mm) was larger compared to `Morado' (23.6 mm) and 'Solo' (23.1 mm). Seven characteristics, namely plant height (about 100 cm), petiole length (35-36 cm), leaf length (27-28 cm), leaf width (36-37 cm), stem site pigmentation (mostly lower), high plant vigour, and flower sex forms (female and hermaphrodite) were common to `Morado' and F, hybrid. Four characters in the F, hybrid namely stem color, petiole color, leaf shape, and flower color were intermediate between `Morado' and 'Solo'. All the parentals and F, hybrid had the same number of main veins (7), flowers per node (multiple), type of flowering (inflorescences), and petiole hairs (absent) character. For the chromosomal analysis, there was a prevalence of nine bivalents in the cells at diakinesis of `Morado', 'Solo', and their F, hybrid and therefore a diploid chromosome number of 2n=18. Majority of the cells undergoing meiosis I in `Morado' (96.0%), 'Solo' (100%) and their F, hybrid (89.7%) were normal. Univalent formation (23.5%) at diakinesis, laggards (17.6%) at metaphase I, and early disjunction of chromosomes at anaphase I (6%) were observed in the F1 hybrid. Determination of pollen fertility revealed that the parentals had high average pollen fertilities, 95.30% for `Morado' and 96.86% for 'Solo' while the F1 hybrid had 83.96%.

Language

English

Location

UPLB Main Library Special Collections Section (USCS)

Call Number

Thesis

Document Type

Thesis

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