Search Results

You are looking at 51 - 60 of 145 items for

  • Author or Editor: John Clark x
Clear All Modify Search

Eleven muscadine grape (Vitis rotundifolia Michx.) cultivars were evaluated in Nov. and Dec. 1994 and Jan. and Feb. 1995 for primary bud hardiness using differential thermal analysis. Vines sampled were located at the University of Arkansas Fruit Substation, Clarkeville. Data analysis indicated a significant date × cultivar interaction for mean low temperature exotherm (LTE). Mean LTE decreased for all cultivars during the sampling period. Hardier cultivars for November and December were `Sterling' and `Summit'; for January, `Nesbitt', `Summit', `Carlos', and `Sterling'; and for February, `Sugargate', `Carlos', and `Summit'. The minimum LTE for any cultivar was – 23.8C for `Sugargate' during February.

Free access

The University of Arkansas (UA) blackberry breeding program began in 1964, with the aim to provide high-quality fruit to the fresh market industry. One of the important traits for successful blackberry (Rubus subgenus Rubus Watson) postharvest handling is flesh firmness, so developing cultivars with high firmness is a top priority for the fresh market blackberry breeding programs across the world. In particular, the Arkansas blackberry program has a wide range of genotypes with exceptional firmness characteristics, including fruit with a unique crispy texture and firmness. During 2013 and 2014, fruit firmness measurements were done on 15 Arkansas genotypes including those with crispy and noncrispy textures. Firmness measurements consisted of fruit compression, skin drupelet penetration, and receptacle penetration. Confocal photos were taken on sections of berries of a subset of crispy and noncrispy genotypes, and color reversion was evaluated among these genotypes after storage. Compression force values differentiated crispy and noncrispy genotypes, with average values of 11.8 Newton (N) and 8.0 N, respectively. Drupelet penetration force was also higher for crispy genotypes averaging 0.23 N and noncrispy 0.15 N; similarly, receptacle penetration force averaged 0.20 N for crispy and 0.18 N for noncrispy genotypes. Visual inspection of fruit tissue revealed that drupelet mesocarp cells and receptacle cells and cell walls of crispy genotypes maintained their structure during ripening and did not break apart, whereas noncrispy genotypes did not maintain their structure and cellular integrity. Color reversion is a postharvest disorder in which drupelets of blackberry fruits turn red after being black at harvest. Therefore, it has a negative impact for growers, shippers, and consumers. After storage at 5 °C for 7 days, crispy genotypes expressed low levels of reversion compared with noncrispy genotypes. For crispy genotypes, 13.2% of drupelets developed color reversion, whereas a 41.0% developed this disorder in noncrispy genotypes, implying a better postharvest potential of this texture.

Free access
Authors: and

Blue Ridge, Cape Fear, Georgiagem, and O Neal southern highbush blueberry cultivars were grown for 5 years on a fine sandy loam soil in a comparison of plants either mulched with uncomposted pine sawdust and woodchips or nonmulched. Other cultural practices were identical and all plants received the same amount of trickle irrigation. A significant mulch × cultivar interaction for yield and mulch × plant age interactions for yield, individual berry weight, and plant volume were found. Cape Fear was the highest-yielding mulched cultivar, followed by Blueridge, Georgiagem, and O Neal. Mulched plants had higher yields and produced larger plants. Average individual berry weight was greater for mulched plants in the first year of harvest, but not different among treatments in other years. The data reveal that these southern highbush cultivars performed similar to northern highbush (Vaccinicum corymbosum L.) in their need for mulching for adequate production on upland soils.

Free access