Cross compatibility of elite papaya inbred lines to an interspecific hybrid of Carica papaya L. x Carica quercifolia (Saint-Hil.) Hieron

Cross compatibility of four papaya inbred lines to interspecific hybrid 410. 14.06 was studied. Genotypic differences of four inbred lines were determined. Likewise, morphological characterization of parental lines and evaluation of papaya ringspot virus disease resistance and pollen viability of line 410.14.06 under local condition were investigated. Significant difference in all morphological quantitative characters among four papaya inbreds as well as between papaya and F1 interspecific hybrid line 410. 14.06 were observed. Traits that can differentiate line 410. 14.06 from inbred lines (4108, 4172, 5648, and 5893) were sex types, flower color, flower size, and tree habit. Dendrogram of qualitative and quantitative traits showed similar clusterings. The group of papaya inbred lines was divided into two clusters separating inbreds derived from local selections (4108 and 4172) and inbreds that were from other countries (5648 and 5893). Line 410. 14.06 had a separate cluster. The genotypic compatibility among four crosses between interspecific hybrid (C. papaya L. x C. quercifolia) and all inbreds was evident. All crosses produced normal fruits with seeds. However, only inbreds 4108 and 4172 produced well-developed embryos when with line 410. 14.06. Embryos that were 90-120 days old developed into plantlets grown in vitro. Parthenocarpy was observed in all inbred parents. All inbreds in the field developed papaya ringspot disease symptoms. Symptomatology and serological test by Enzyme Linked Immunosorbent Assay (ELISA) confirmed that line 410. 14.06 plants have resistance against PRSV-P. Pollen viability assays showed some number of viable pollens of the interspecific hybrid under local condition. Hence, inbreds 4108 and 4172 may be recommended in papaya wide hybridization. Further studies on inbreds 5648 and 5893 should be conducted to clarify the physiological and environmental factors that may enhance their cross compatibility with interspecific hybrids