DIFFERENTIAL SENSITIVITY OF PAPAYA VARIETIES IN EXPRESSION OF BORON DEFICIENCY SYMPTOMS

CHAN, Y.K. and RAVEENDRANATHAN, P.

SUMMARY

Four varieties of papaya were tested in a peat area at the MARDI Research Station at Jalan Kebun Klang. Boron deficiency symptoms manifested as 'bumpy' fruits were observed in all the varieties. Each variety, however, exhibited a differential sensitivity to the expression of symptoms at various levels of petiole boron. Maradol was the most sensitive variety while Backcross Solo was the least. The former requires at least 18 ppm of boron in petiole tissues before fruits were free of symptoms while in the latter fruit deformation did not occur even at petiole boron level as low as 8 ppm. For three of the tested varieties, expression of deficiency symptoms were found to be strongly correlated with petiole boron levels (-0.5092** to - 0.7759*). No relationship, however, was found between petiole and soil levels of this microelement. The significance of the findings in terms of recommendations of varieties for areas with inherent low boron was discussed.

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