RAPD analysis of somaclonal variants derived from embryo callus cultures of peach.

Peach [Prunus persica (L.) Batsch] regenerants from cv 'Sunhigh' embryo no. 156, regenerants obtained from cv 'Redhaven' embryo no.

Factors Influencing Emergence of Juveniles from Cysts of Heterodera zeae.

Several factors were studied to determine their effects on hatch and emergence of second-stage juveniles (J2) from cysts of Heterodera zeae. The optimum temperature for emergence of J2 from cysts of H. zeae was 30 C.

A method for recovery and counting of nematode cysts.

A technique was developed in the early 1980's for recovery and quantification of Heterodera glycines (soybean cyst nematode) cysts from soil and soybean roots. Cysts were collected on sieves and counted on lincd filter paper. This technique could be applied to other particles of similar dimension and density.

Optimal Levels of Meloidogyne incognita Inoculum for Infection of Tomato and Peach in Vitro.

Penetration of second-stage juveniles (J2) of Meloidogyne incognita into tomato root explants and in vitro propagated peach plantlet roots were compared. Five inoculum levels were used: 25, 50, 75, 100, and 200 J2 for tomato; and 50, 100, 200, 500, and 1,000J2 for peach. The greatest root penetration into tomato was 30% at the 75 J2 level, but the maximum penetration into peach roots was only 8% at the 200 J2 level.

Plant and soil nematodes: societal impact and focus for the future.

Plant and soil nematodes significandy impact our lives. Therefore, we must understand and manage these complex organisms so that we may continue to develop and sustain our food production systems, our natural resources, our environment, and our quality of life. This publication looks specifically at soil and plant nematology.

Survey for Heterodera glycines in Maryland.

Soybean cyst nematode, Heterodera glycines, was detected in 116, or 25%, of 463 soil samples collected in eight of the nine counties east of the Chesapeake Bay in Maryland.

Resistance in Zea mays to Heterodera zeae.

Twenty-three precommercial field corn lines (Zea mays) were screened in the greenhouse and in vitro for the ability to support reproduction of Heterodera zeae. Although H. zeae reproduced on all corn lines, reproduction was only 0.

Reproduction of Heterodera zeae and Its Suppression of Corn Plant Growth as Affected by Temperature.

Reproduction of the corn cyst nematode (Heterodera zeae) and its effect on growth of corn (Zea mays) was studied in plant growth chambers at 24, 27, 30, 33, and 36 C. Reproduction of H. zeae increased directly with increase in temperature from 24 to 36 C.

Temperature and the Life Cycle of Heterodera zeae.

Development of the corn cyst nematode, Heterodera zeae, was studied in growth chambers at 20, 25, 29, 33, and 36 +/- 1 C on Zea mays cv. Pioneer 3184. The optimum temperature for reproduction appeared to be 33 C, at which the life cycle, from second-stage juvenile (J2) to J2, was completed in 15-18 days; at 36 C, 19-20 days were required.

Survival of Heterodera zeae in Soil in the Field and in the Laboratory.

Eggs and (or) second-stage juveniles (J2) inside cysts of Heterodera zeae survived over winter in the field with no detectable mortality at all six depths to 30 cm from which soil samples were collected between corn stubble in the row at 4-8-week intervals. Few or no free J2 were recovered from soil collected in January-April from the top 5 cm, but some were recovered at all samplings from soil collected at greater depths. Emergence of J2 from cysts and numbers of females developing on corn roots in bioassays of cysts increased substantially between January and April.

Investigations of the Host Range of the Corn Cyst Nematode, Heterodera zeae, from Maryland.

The host range of the corn cyst nematode, Heterodera zeae, recently detected in Maryland, was investigated. A total of 269 plant entries, representing 68 families, 172 genera, and 204 species, was inoculated with cysts or a mixture of eggs and second-stage juveniles of H. zeae.

Pinewood Nematode, Bursaphelenchus xylophilus, Associated with Red Pine, Pinus resinosa, in Western Maryland.

Red pines Pinus resinosa in Garrett and Allegany counties, Maryland, were examined during 1982-84 to determine distribution of the pinewood nematode, Bursaphelenchus xylophilus, within and among trees. Approximately 25-year-old (younger) and 47-year-old (older) trees were subdivided into the following categories: 1) trees with mostly green needles; 2) trees with mostly reddish-brown needles; 3) trees lacking needles but with bark intact; 4) trees lacking both needles and bark; and 5) trees with chlorotic, bleached-green needles. Bursaphelenchus xylophilus was found infecting 68% of younger red pines and 77% of older red pines.

Diacyl, Alkylacyl, and Alkenylacyl Phospholipids of Meloidogyne javanica Females.

The phospholipid composition and acyl, alkyl, and alkenyl group compositions of diacyl, alkylacyl, and alkenylacyl phosphoglycerides of M. javanica were investigated. Phospholipid was comprised of 61.

Pectolytic enzymes in three populations of Ditylenchus dipsaci.

Extracts of nematodes of the Raleigh, North Carolina (RNC), Waynesville, N. C. (WNC), and onion populations of Ditylenchus dipsaci were examined for pectolytic activity.

Organic Acids of Ditylenchus triformis and Turbatrix aceti.

Pyruvic acid, lactic acid and several tricarboxylic acid cycle acids were extracted from Ditylenchus triformis and Turbatrix aceti and identified. Fumaric acid was predominant in both nematodes. Small amounts o f malic and alpha-ketoglutaric acids and intermediate quantities o f lactic, citric, succinic, and pyruvic acids occurred in D.

Disc-electrophoretic Patterns of Enzymes and Soluble Proteins of Ditylenchus dipsaci and D. triformis.

Soluble protein, esterase and oxidative enzyme patterns of the Waynesville, North Carolina, (WNC) and Raleigh, North Carolina, (RNC) populations of Ditylenchus dipsaci were compared. Polyacrylamide gel electrophoretic patterns of soluble protein extracts of nematodes of the two populations differed. Esterase and catalase patterns, however, were identical.