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  • Author or Editor: Raymond G. Lockard x
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Abstract

Comparisons were made of the fresh weights of trees on apple rootstocks MM 111, MM 106 and M.9 and of the weights of trees with interstocks of ‘Red Delicious’ (RD), MM 106 and M.9 of 2.5, 7.5, 12.5 or 18 cm lengths on MM 111 rootstocks. All scions were RD and the experiment covered the 1969-1972 growing seasons. Weight of all plant parts increased over the 4 years but the percentage of leaves and new growth decreased from 1970 to 1972, whereas the increase in scion and interstock weight tended to be a greater percentage of total plant weight increase (TPI) each year. Treatments MM 106 and M.9 rootstocks and M.9 interstock dwarfted the trees 37, 40, and 40 percent, respectively. M.9 rootstock and interstock and MM 106 interstock increased in weight proportionately more than comparable parts on the least dwarfing graft combinations. M.9 interstock also induced a proportionately larger root system than the other 2 interstocks.

The faster growth rate of plants on MM 111 rootstock resulted from more rapid growth of woody tissues; leaf weights were similar. Plants with an RD or MM 106 interstock showed numerous variations in growth over the 4 years, but those with an M.9 interstock were uniform in growth habit.

Plants with a 12.5 cm interstock weighed the least of all 3 interstock types. A comparison of weight of plants with a 2.5 or 7.5 cm interstock with those with a 12.5 or 18 cm interstock showed a reduction in growth due to the longer interstems only on plants with an M.9 interstock.

Open Access

Abstract

The levels of total free amino acids, arginine, aspartic acid, glutamic acid, serine and protein were determined in the roots of apple plants grafted with (a) rootstocks of MM 111, MM 106 or EM IX or (b) rootstock MM 111 plus interstems 1, 3, 5, or 7 inches long of ‘Red Delicious’ (RD), MM 106 or EM IX; all scions were RD. The levels of free amino acids and protein in the rootstocks were not related to their dwarfing effect. The level of free amino acids was very low in MM 106. The levels of free amino acids in the roots of plants with MM 106 interstem increased as the interstem was increased in length. Plants with EM IX interstem had high and nearly equal levels of free amino acids in the roots when the interstem was 3, 5, or 7 inches long, but there was a much lower level in the roots of plants with a 1-inch interstem. The levels of protein in the roots of plants with MM 106 or EM IX interstem showed smaller differences but followed the same pattern as that of free amino acids. Among control plants free amino acids and protein were lower in roots of plants with 2 grafts than in those with 1 graft, and free amino acids were lower in the roots of those with 5- and 7-inch interstems than in those with 1- and 3-inch interstems. The levels of individual amino acids were variable, but the levels of aspartic acid and serine followed a pattern similar to that of total free amino acids.

Open Access

Abstract

Comparisons were made of MM.111, MM.106 and EM.IX as rootstocks and ‘Red Delicious’ (RD), MM.106 and EM.IX as 1-, 3-, 5- and 7-inch interstems. The dwarfing effects of the rootstocks were greater than those of the interstems. Interstems reduced the growth of most plant parts in direct proportion to the degree of dwarfing of the interstem and there were few significant differences among plants with different interstem lengths. However, plants with interstems of 1 and 3 inches had higher percentage increases in root weight than those with 5 and 7 inch interstems. Plants with EM.IX interstems showed similar patterns of total plant, leaf and new growth weights. Weight increases of RD interstems were lower than those of MM. 106 and EM.IX interstems. The EM.IX rootstock weights were 101 percent of the weights of the plant tops, whereas rootstock weights were approximately 50 percent of the weights of plant tops for all other treatments.

Open Access