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  • Author or Editor: Alfred Jones x
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Sweetpotato [Ipomoea batatas (L.) Lam.] cultivars with high levels of resistance to root damaging insects have been developed through the collaborative efforts of a multidisciplinary research team. These resistances were combined with other traits necessary for a successful cultivar such as: disease resistances; high yield; long storage life; prolific sprout production; marketable root size, shape and skin at tributes; and culinary excellence. Adpotion of quantitative genetic principles, development of a wide gene base, sequential selection schemes, use of effective selection criteria and appropriate susceptible standards contributed to the program's success. These achievements were made with, little prior knowledge about inheritance patterns, gene action, mechanisms of resistance or a complete knowledge of the insects concerned. The value of insect resistant cultivars has become better appreciated with the recent decrease in chemical alternatives.

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Author:

Sweetpotato [Ipomoea batatas (L.) Lam.] cultivars with high levels of resistance to root damaging insects have been developed through the collaborative efforts of a multidisciplinary research team. These resistances were combined with other traits necessary for a successful cultivar such as: disease resistances; high yield; long storage life; prolific sprout production; marketable root size, shape and skin at tributes; and culinary excellence. Adpotion of quantitative genetic principles, development of a wide gene base, sequential selection schemes, use of effective selection criteria and appropriate susceptible standards contributed to the program's success. These achievements were made with, little prior knowledge about inheritance patterns, gene action, mechanisms of resistance or a complete knowledge of the insects concerned. The value of insect resistant cultivars has become better appreciated with the recent decrease in chemical alternatives.

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Abstract

Awareness that the continuous variation of morphological traits in sweet potato can best be explained and studied with quantitative genetics has increased during the last 20 years (10, 16). This paper has 2 purposes: 1) to summarize available heritability estimates for traits of sweet potato and 2) to alert breeders to their use and application in crop improvement.

Open Access

Abstract

Sweetpotato breeders are confronted with the problem of extremely low seed set. Based on counts made of seed set in tagged flowers, only about 2 or 3% of the potential seed production is realized (2). This problem is compounded by the occurrence of flower bud abscission prior to opening. Although low seed set may be primarily due to genetic incompatibility, sterility or physiological disharmony in developing seed, insect or disease damage could also be involved. This study provides information on the fungi of sweetpotato floral parts and preliminary results of their effect on seed set.

Open Access
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Abstract

Viability studies were conducted on 18 lots of seed of sweet potato (Ipomoea batatas (L). Lam.) spanning a 21 year storage period. For the last 10 years, these seeds had been stored at 18° C and 45-50% relative humidity, but prior to that storage conditions varied. Weight per 100 seeds ranged from 1.7 to 2.4 g. No effect of seed age was found on germination (radical protrusion), which averaged 90% after sulfuric acid scarification, or on emergence which averaged 72%. The condition of the seed prior to storage seemed to have more effect than how long they were stored.

Open Access

Previous work in this laboratory identified high levels of unreduced (2n) pollen in the tetraploid (4×) Ipomoea spp. Acc. 81.2. This work provided indirect evidence that 2n pollen was involved in the evolution of the 6x ploidy level of the cultivated sweetpotato (I. batatas). To further study the role of 2n pollen in sweetpotato evolution, we examined plants of Acc. 81.2. plants of five sweetpotato cultivars, and 100 randomly selected heterozygous sweetpotato seedlings. The 4× Acc. 81.2 was determined to be I. batatas. High levels of large 2n pollen were confirmed in Acc. 81.2, and low levels of 2n pollen were observed in `Sulfur' and in 16% of the sweetpotato seedlings. Presence of monad, dyad, and triad sporads confirmed that the large 2n pollen grains were the result of nonreduction in the sporad stage. These new findings are direct evidence that 2n pollen was involved in the evolution of the 6× ploidy level of sweetpotato. This is the first report of a 4× accession classified as I. batatas; it is also the first report of 2n pollen in 6× I. batatas The widespread presence of 2n pollen in sweetpotato suggests that the trait can be used to advantage in breeding programs to introgress genes from wild 4× Ipomoea spp. into cultivated 6× sweetpotato without adverse effects on genetic stability or fertility.

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Abstract

Application of systemic fungicides to sweet potato (Ipomoea batatas (L.) Lam.) increased the total number of healthy seed harvested 50% by increasing pod set, number of seed per pod and the proportion of healthy seed. Insecticides aldicarb and naled gave dramatic responses and increased the number of seedlings obtained per parent plant 2- to 5-fold. Insect damage appeared to be an important cause of low seed set and low seed quality in sweet potato.

Open Access

Abstract

Two breeding lines of sweet potato [Ipomoea batatas (L.) Lam.] were released in 1975. They possess unusual combinations of disease and insect resistances with other useful characteristics. Both lines originated from mass selection for multiple disease and soil insect resistances in a sweet potato population incorporating a wide gene base. Both lines flower and set seed without any special treatment; traits of particular value in breeding

Open Access

The reactions of eight sweetpotato [Ipomoea batatas (L.) Lam.] introductions were categorized for root damage by wireworms, Diabrotica sp., Systena sp. (WDS), sweetpotato flea beetle (SPFB), and grubs. Clones were compared with resistant (`Regal') and susceptible (`SC-1149-19') entries. The number of resistant clones for the WDS, SPFB, and grubs were three, four, and one, respectively, intermediate five, four, and one, and susceptible zero, zero, and six, respectively. This test demonstrated that significant levels of soil insect resistance exist in these sweetpotato introductions for use by plant breeders.

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