Upper Mid-Crown Yellowing (UMCY), needle retention, and foliar chemistry were determined for Pinus radiata D.Don clones at the Kaingaroa Seed Orchard in the central North Island of New Zealand. These clones had been Propagated as rooted cuttings and grafts. UMCY was found to be under both environmental and genetic control, with clone accounting for around half of the variation at this site. The broad-sense heritability of UMCY was 59%. Nutrient concentrations in two needle age-classes from the upper and lower crown were measured in four ramets of each of 17 clones selected to cover the range of UMCY severity. There was a negative correlation between UMCY and magnesium (r = -0.60, n = 17, p = 0.01), and a positive correlation with potassium (r = 0.56, n = 17, p = 0.05) and nitrogen (r = +0.75, n = 17, p = 0.01) in upper crown foliage, with the correlations based on clone means. UMCY was absent in clones where foliar magnesium concentrations in 1-year-old needles from the upper crown exceeded 0.10%, but increased with decreasing foliar magnesium, particularly in clones with high foliar potassium or nitrogen. Unknown clonal factors were also involved in UMCY. Broad-sense heritabilities of foliar nutrients were high for potassium, magnesium and calcium (particularly in the lower crown position of trees grown from cuttings), and moderate for other nutrients. Clone means of foliar nutrients differed by more than a factor of two for potassium, magnesium, calcium, boron, and manganese. Marked differences were found between upper and lower crown positions for most nutrients. The scion played a major role in determining foliar magnesium, potassium, manganese, and copper concentrations, while the root stock/graft union played a major role for calcium, zinc, and to a lesser extent nitrogen and phosphorus. Needle retention was also highly clonal, with a broad-sense heritability of 68%. Clones with low needle retention had higher potassium concentrations, both in upper and lower crown foliage, and significantly more UMCY than healthy clones. Part of the clonal variation in diameter at breast height (dbh) was related to UMCY, with healthy clones being larger in mean dbh than clones with severe UMCY. Dbh increased with increasing needle retention, while the concentrations of foliar nitrogen, phosphorus, and potassium correspondingly decreased. We conclude that some genotypes of P. radiata are pre-disposed to UMCY at this site, owing to the high K:Mg and N:Mg ratios in upper crown foliage. Large clonal variation in UMCY indicates that considerable opportunity exists for improving tolerance to UMCY through vegetative propagation of tolerant P. radiata genotypes.