scholarly journals Heterosis and combining ability for storage root, flesh color, virus disease resistance and vine weight in Sweet potato [Ipomoea batatas (L.) Lam.]

2020 ◽  
Vol 15 (2) ◽  
pp. 187-202
Author(s):  
Ba Aliou ◽  
C. Gemenet Dorcus ◽  
Onguso Justus ◽  
Diouf Diaga ◽  
Mendes Thiago ◽  
...  
2021 ◽  
Vol 22 (9) ◽  
pp. 4826
Author(s):  
Yang Gao ◽  
Zhonghou Tang ◽  
Houqiang Xia ◽  
Minfei Sheng ◽  
Ming Liu ◽  
...  

A field experiment was established to study sweet potato growth, starch dynamic accumulation, key enzymes and gene transcription in the sucrose-to-starch conversion and their relationships under six K2O rates using Ningzishu 1 (sensitive to low-K) and Xushu 32 (tolerant to low-K). The results indicated that K application significantly improved the biomass accumulation of plant and storage root, although treatments at high levels of K, i.e., 300–375 kg K2O ha−1, significantly decreased plant biomass and storage root yield. Compared with the no-K treatment, K application enhanced the biomass accumulation of plant and storage root by 3–47% and 13–45%, respectively, through promoting the biomass accumulation rate. Additionally, K application also enhanced the photosynthetic capacity of sweet potato. In this study, low stomatal conductance and net photosynthetic rate (Pn) accompanied with decreased intercellular CO2 concentration were observed in the no-K treatment at 35 DAT, indicating that Pn was reduced mainly due to stomatal limitation; at 55 DAT, reduced Pn in the no-K treatment was caused by non-stomatal factors. Compared with the no-K treatment, the content of sucrose, amylose and amylopectin decreased by 9–34%, 9–23% and 6–19%, respectively, but starch accumulation increased by 11–21% under K supply. The activities of sucrose synthetase (SuSy), adenosine-diphosphate-glucose pyrophosphorylase (AGPase), starch synthase (SSS) and the transcription of Susy, AGP, SSS34 and SSS67 were enhanced by K application and had positive relationships with starch accumulation. Therefore, K application promoted starch accumulation and storage root yield through regulating the activities and genes transcription of SuSy, AGPase and SSS in the sucrose-to-starch conversion.


1970 ◽  
pp. 01-05
Author(s):  
Ncube Netsai ◽  
Mutetwa Moses, Mtaita Tuarira

There is significant variation in yield of storage roots and vines of sweet potato (Ipomoea batatas) among farmers due to use of different cutting positions and pruning of vines at different levels. This study was carried out to establish the cutting position and the vine pruning level that give the best yield of both the storage roots and vines. The study was conducted in a 3x3 factorial arrangement in Randomized Complete Block Design (RCBD) with three replications. Treatments included cutting position at three levels (apical cutting, middle cutting and basal cutting) and pruning at three levels, 0%, 25% and 50% respectively. Pruning was done. 50 days after planting. And storage root harvesting was done 100 days after planting. The two measurements were summed up to give the total vine weight. Storage root length, diameter and weight were measured at 100 DAP. Storage root length indicated significant difference (P<0.05) only among cutting positions with highest mean length (16.20 cm) obtained from apical cutting and the lowest (11.98 cm) from basal cutting. Storage root diameter, storage root weight and vine weight indicated significant interaction (P<0.05) of cutting position and vine pruning level. Highest mean root diameter and root weight were obtained from middle cutting and 25% vine pruning level, with the lowest being obtained from basal cutting and 50% vine pruning level. Highest vine weight was recorded from middle cutting and 50% vine pruning level, with the lowest being recorded from basal cutting and 0% vine pruning level. Both middle and apical stem cuttings can be recommended for higher storage root and vine yield. Vine pruning at 25% can be adopted for higher storage root yield while pruning at 50% can be suggested for higher vine yield.


1970 ◽  
Vol 28 (3) ◽  
pp. 363-374
Author(s):  
J. Ssengo ◽  
P. Wasswa ◽  
S.B. Mukasa ◽  
A. Okiror ◽  
S. Kyamanywa

Sweetpotato (Ipomoea batatas Lam.) production is greatly constrained by viral infections, especially Sweet potato feathery mottle virus and Sweet potato chlorotic stunt virus that synergistically cause a severe sweetpotato virus disease. The impact of viruses is aggravated by the vegetative nature of the crop and inaccessibility to dependable diagnostic tools in rural areas where sweetpotato production is done. This makes it hard for seed inspectors to perform quality checks prior to use of vines for planting. The objective of this study was to develop a procedure that allows for detection of sweetpotato viruses on-site. This involved modification of the Lodhi et al. (1994) nucleic acid extraction procedure, by omitting some of the laboratory specific steps and varying the incubation time in liquid nitrogen, instead of the freezer. Incubation in liquid nitrogen for only 1.5 hours yielded as high quality RNA compared to that of the original protocol, when incubation was done at 4°C overnight in a freezer. Reverse transcriptase (RT) was run using a portable miniPCR thermocycler; and the resulting cDNA was amplified using this miniPCR machine instead of using a laboratory stationed conventional PCR thermocycler. The cDNA was efficiently amplified and amplicons were similar to those obtained with the original extraction protocol and subsequent amplification by the conventional RT-PCR. Our protocol reduced extraction time from about 16 hours for the original protocol, to about 2 hours and 45 minutes. If this tool is utilised by the crop protection departments, we believe it will contribute greatly towards sustainable sweetpotato production through making timely recommendations.


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