Abstract
Like high yielding variety, quality planting material is also one of the key factors to
improve yield of citrus fruits in Bangladesh. Therefore, this study was conducted in
order to select high yielding genotypes of pummelo as well as to produce citrus greening
disease free quality planting materials of sweet orange. To achieve these goals, five
experiments were conducted at Bangladesh Agricultural University Germplasm
Center (BAU-GPC), Mymensingh and fruit research division of Bangladesh
Agricultural Research Institute (BARI), Gazipur during 2016 to 2019. Experiments 1
and 5 were conducted following randomized complete block design with three
replications. From experiment 1, rsults showed that BAU Accession-111 yielded the
highest fruit weight (40.50 kg/plant) and number of fruit per plant (60) and BAU
Hybrid Jambura showed the highest fruit weight (1215.33 g), pulp weight (519.91 g)
and weight of 100 seeds (78.31 g). But BAU Mohini Jambura performed the lowest in
respect of number of fruit per plant, fruit weight, pulp weight, fruit yield per plant and
weight of 100 seeds. These phenomenon also observed in Principal Component
Analysis-Biplot (PCA-Biplot). It was found that BAU released pummelo varieties also
performed better in respect of qualitative and quantitative traits of fruits. The residual
effect (R) of path analysis indicated that the characters under the sfudy contributed to
98.38% of the fruit yield per plant. In experiment 2, the result revealed that all the 5
SSR primers (TAA41, CMS21, ССТ01, ТАA27 and CAC23) showed clear band and
polymorphism for 21 pummelo genotypes analyzed but no heterozygosity was
observed. The Polymorphic Information Content (PIC) values ranged from 0.66
(CAC23) to 0.88 (TAA41) while gene diversity value ranged from 0.89 (TAA41) to 0.72
(TAA27). BAU Accession-13 and BAU Hybrid Jambura found more genetic distant
relationships to others and formed single cluster respectively in the Neighbor-joining
tree. In experiment 3, results showed that zygotic seedlings did not detect by SSR
primers (TАA41, СAC23, ТАA27 and TAA45) in PCR amplification of the DNA from
seven seedlings, which were emerged from three seeds of open pollinated sweet
orange mother plant respectively. Single band was formed and no hybrid origin was
found in gel documentation. In experiment 4, a band about 703 bp found in
electrophoresis which was alike to the size of the band of Candidatus Liberibacter
asiaticus (CLas) and confirmed greening diseases. This result helped to produce
greening diseases free saplings by diagnosis of healthy scion plants of sweet orange,
rough lemon rootstocks and their grafts. In experiment 5, it was noticed that the
combination of sweet orange scion grafted on seven months old rough lemon rootstock
was the best among the other combinations as it gave 80% graft survivability and other
superior performances on the plant height, number of leaves per plant, canopy volume
and content of leaf Chlorophyll b. In conclusion it can be stated that distinct morphomolecular variations existed among the tested pummelo germplasm. Citrus greening
free saplings can be produced through grafting followed by moleculer diagnosis.
Seven months old rough lemon can be used as rootstock for grafting of sweet orange.