Ferweez, H.M. * ; A.M.El Gomaa and A.M.A. El.Shafai

Yield and technological quality characteristics of some sugar beet cultivars as affected by planting and harvesting dates under Middle Egypt conditions

Ferweez, H.M. * ; A.M.El..Gomaa and A.M.A. El.Shafai

* Sugar Crops Res. Inst., Agric. Res. Center, Egypt.

ABSTRACT

Two field experiments were conducted at Malawi Agric. Res., Station, Minia governorate , Egypt during 2002/2003 and 2003/2004 seasons. Our objective was to evaluate effect of planting and harvesting dates on yield, physical properties and chemical composition of some sugar beet cultivars to selecting the optimal planting and harvesting dateswhich help grower to increasing it income. Planting dates were,15/9 ,15/10 and 15/11. Harvesting dates were 180 , 195 and 210 days and the studied cultivars of sugar beet were Gloira, Oscar poly , Allexa and Sofie cultivars.

The obtained results indicated that a significant differences in productivity traits ,i.e. roots, recoverable sugar and top yields (ton/fed.) as well as technological quality characteristics( Rendement , sugar loss %, quality index , pol% and fiber%)of the studied sugar beet cultivars amongdifferent sowing and harvesting dates.

It could be noted that the highest values of roots and recoverable sugar yields (ton/fed) as well as pol%, rendement and quality index of sugar beet were achieved with sowing sugar beet on 15th October followed by 15th September and 15th November , harvesting at age 195 days followed by 210 and 180 days with Gloria cultivar followed by Oscar poly , Allexa and Sofie cultivars,respectively . Therefore, early sowing on 15th October and 15th Septemberand harvest at 195 days with Gloria cultivar and Oscar poly cultivar is preferable and recommended for increasing the sugar production and grower income.

Keywords:Sugar beet,planting date ,harvesting date,cultivar, rendement andquality index.

INTRODUCTION

After introducing sugar beet(Beta Vulgaris L.) in Egypt and its success as the second source of sugar production as well as its more adaptability to our environmental factors such as Middle Egypt conditions, it became the second source for sugar industry .Abou-Qurkas Sugar Factory, El.Minia Governorate is the only factory in Egypt , where sugar cane and sugar beet are together processed.Sugar beet has been cultivated as sugar crop in Egypt on a large scale since 1981 as a source for sugar production. Production of beet sugar in 2003 season is represented 28.5% of the total local sugar production which reached about 1.4 million tons. Pioneer trails proved its suitability to our edaphically conditions in winter season , but the rotation system makes it as a competitor cropto the main strategic feeding crops either human feeding or animal feeding,i.e.wheat and clover (Gobarh,2001;El.Harriri & Gobarh ,2001 ; Gobarh & Thalooth, 2001; CCSC,2003 and Ramadan, et. al. 2003) .

Sugar beet plants grow well in the period from 1st September till 15 December under El.Minia Governorate conditions and still in the field about 7 months . starting the sowing date in 15th September till 15th November will save appropriate chance for continuous delivery as long as possible during the industrial season to reducing the large loss in yield and quality of sugar beet post-harvest under Middle Egypt conditions.Early planting of sugar beet at 1st October increased most of yield attributes( roots and theoretical sugar yields) and good quality parameters (Abou- Salama & El.Syiad, 2000 and Abou- El.Magd,et. al.2003) .

Harvesting date is also an important factor which affected grow yield and quality of sugar beet (Albinet,1993;Jaszcolt,1997;Lauer,1997; Besheit & El.Gharbawy 1991 and Hassanin ,1999) . Abou- Salama & El.Syiad, (2000) demonstrated that harvest dates did not significant affect root yield despite its highly significant effect on theoreticalsugar , quality index and sugar yield /fed . They added that quality index was at its maximum in late harvesting .i.e. 210 days , due to low values of impurities associated with this date .In contract ,Gobarh,( 2001 ), revealed that roots and sugar yields ; TSS% , sugar recovery% , pol% and impurities ,i.e. α – amino N , K and Na contents of sugar beet showed significant response to harvest dates. He reported that roots and sugar yields ,TSS% , sugar recovery% and pol% of sugar beet increased as harvest date delayed ,while the impurities ,i.e. α – amino N , K and Na contents of sugar beet significantly decreased with delaying harvest from 180 to 210 days after sowing .

Genotypes of sugar beet had a clear influence on quality . Varietal differences were also significant in response to planting and harvest dates .Gazelle produced maximum roots yield of 30.9 tons/fed was produced by Oscar poly due to its high theoretical sugar and quality index values . Differences in quality measurements were also highly significant among varieties .The choice of one variety in a certain location should be based on its performance in relation to planting and harvesting dates .Such decision should also take in account the available time according to the preceding and following crops in the rotation (Mokadem,1993; Marlander & Rover, 1994;Srba,1995; Kerr& Leaman, 1996 and Abou- Salama & El.Syiad, 2000) .

Great efforts are spent to increasing productivity and quality of sugar beet especially under Middle Egypt conditions i.e. El.Minia Governorate conditions . So, our objective was to evaluate effect of planting and harvesting dates on yield, physical properties and chemical composition of some sugar beet cultivars to selecting the optimal planting and harvesting dateswhich help grower to increasing it income.

MATERIALS AND METHODS

This work was carried out at the Mallawi Agricultural Research Station, El-Minia,Egypt, toevaluate effect of planting and harvesting dates on yield, physical properties and chemical composition of some sugar beet cultivars.This work was laid out in a split-split plot design with four replicates. Planting dates were,15/9 ,15/10 and 15/11arranged in the main plots during the two seasons of 2002/2003 and 2003/2004.Harvesting dates were 180 , 195 and 210 days occupied in the subplots. The studied cultivars of sugar beet ,i.e. Gloira, Oscar poly , Allexa and Sofie cultivars, allocated in the sub sub-plots. Sub sub plots (10.5 m2 ) ( five ,60 cm wide rows ,each of 3.5 meters long ). Nitrogen fertilizer in the form of urea(46.5%) was added at the recommended rate of 70 kgs N /fed in two equal doses (the first one after thinning and the second one after 30 days later ).Potassium fertilizer in form of potassium sulfate (48%K2O) at a rate of 24 kg K2O/fed was added after thinning , while phosphorus fertilizer was added at recommended rate of 30 kgs /fed. at planting . Some chemical and physical properties of the experimental soil before soil preparation were estimated according to the procedures outlined by Jackson (1967) are shown in Table (A)

Ta Table (1): Some physical and chemical characteristics of the experimental soils*.

Season 2002/3

Clay %

* Each value represents the mean of 5 samples

The normal cultural procedures of sugar beet crop growing were practiced according to optimum tradition agricultural practices of the region.

Data Recorded:

1-Cleaned roots yield (ton/fed):Sugar beet plants of The three guarded rows were topped, cleaned and weighted to determineCleaned roots yield (ton/fed).

2-Recoverable sugar yield(ton/fed) : It was calculated as in Mohamed, (2002), using the following formula:

Recoverable sugar yield(ton/fed)= Cleaned roots yield (ton/fed) x Rendement

3-Technological quality characteristics:

3.1.physical properties:

3.1.1.Rendement (Recoverablesugar per cent)was calculated using the following equation according to Abou-Shady (1994).

Rendement = Pol, % - [0.29 + 0.343 (K + Na) +  - N (0.094)],

Where K, Na and -N determined as milliequivalent/100 g beet.,

3.1.2-Quality index was calculated as in Abou- Salama and El-Syaid, (2000) using the following formula: Quality index, % = Rendement,% X 100 ÷ Pol, %

3.1.3. Sugar loss % : It was calculated according to Mohamed(2002) using the following formula: Sugar loss per cent = Pol,% - Rendement ,%.

3.2.Chemical analysis :

3.2.1.Sucrose contentwas estimated in fresh samples of sugar beet roots, using saccharometer according to the method described in AOAC, (1995).

3.2.2. Reducing sugars%was estimatedas inthe method described in AOAC, (1995).

3.2.3.Alpha amino nitrogen, sodium and potassium contents were estimated according to the procedure of sugar company by Auto Analyzer as describe in Cooke and Scott, (1993). The results calculated as milliequivalent per 100 gm beet.

3.3.Data collected were subjected to Analysis of Variance (ANOVA). The proper statistical of all data was carried out according. Differences among treatments were evaluated by the least significant difference test (LSD) according to procedure out

lined by Snedecor & Cochran, (1980) and Gomez & Gomez (1983). Significant of differences was defined at 5 per cent level according to Waller and Duncan (1969).

RESULTS AND DISCUSSION

1. Productivity traits:

1.1. Fresh roots yield ( ton/fed)

Fresh roots yield represented the raw material delivered to sugar factory for extraction and production of sugar. So, it is noteworthy to mention that fresh root yield (ton/fed.) represented one of the important factors which affected income of beet grower and sugar production. The data given in Table (1) showed significant differences in this trait at different sowing dates. Root yield of sugar beet increased by 0.82 and 16.33% with sowing sugar beet on 15th October compared with sowing 15th September and November, respectively. This might be mainly due to the early sowing dates at 15th October and September were in the warm weather conditions which encountered within the early part of seedling growth that could boost the growth of seedling before the relatively cooler weather in the late sowing on 15th November (Abou-Salama & El-Syiad, 2000). They pointed out that early planting had maximum values of yield. Here too, Fadel (2002) reported that root yield of sugar beet was significantly affected by different sowing dates. Root yield of sugar beet was relatively higher in sowing sugar beet on 15th October than sowing 15th September but not significant. This may be due to the infection by insects and diseases was higher in sowing sugar beet on 15th September than sowing 15th October. Therefore, sowing sugar beet during September and October months is recommended especially for increasing roots yield and consequently increasing the income of growth.

Regarding harvesting date effect the data in Table (1) showed that there was a significant difference in fresh root yield of sugar beet among the studied there harvesting dates. The present data concluded that fresh root yield (ton/fed.) of sugar beet increased by 19.48 and 3.61% when beet roots harvested at 195 days of age compared with harvest at 180 and 210 days of age, respectively. This may be mainly due to the highest rate of accumulation of reserves in the roots rather than their utilization in respiration when beet roots harvested at 195 days of age (Stancer, 1970 and Nour etal. 1978). In this respect, the hot end of season weather causes senescence of leaves leading to decrease in root yield, leading to decrease in root yield at the late harvesting date and especially at the late sowing date (Abou-Salama & El-Syiad, 2000). Besides, Mohamed (2002) indicated that the decreasing in the root yield (ton/fed.) might be due to the increase in consumption of sucrose throughout or during respiration process.

The selection of the variety that is grown is one of the most important decisions. Therefore, the grower should select variety that is adapted to the growing season in his area. With regard to sugar beet cultivars, the results recorded in Table (1) showed a significant difference between the studied sugar beet cultivars in root yield (ton/fed.). Whereas, Gloria and Oscar poly, had the higher value in this trait than Allexa and Sofie . Gloria cultivar recorded the highest value in root yield among the studied sugar beet cultivars. This difference might be principally due to the genetic variation and the superiority of Gloria in growth parameters (Gaber, etal., 1989 and Basha, 1999). Besides, Abou-Salama & El-Syiad (2001) revealed varietal differences was found in this character.

It was evident that the increase in this trait meant the increase of economical value for yield and income of grower especially when sucrose% of roots would be high. It can be revealed that harvesting sugar beet at 195 days of age is recommended for increase income of grower and followed by harvest of 210 days ofage.

1.2. Top yield (ton/fed.):

Top yield represented the removal parts from the gross plants or biomass yield by cutting which often carried out in the field to reduce the costs of roots transport and sugar consumption by respiration. The significant differences in top yield (ton/fed.) of sugar beet between the studied sowing dates are embodied in Table (3). The top yield of sugar beet was decreased as sowing date delayed from 15th September to 15th November. Such data are in agreement with the findings of several investigators (Azzazy, 1998 and Fodel, 2000). They revealed that delaying sowing date gradually and significantly decreased top yield (ton/fed.) of sugar beet.

Regarding harvesting date effect, the results listed in Table (3) showed a significant difference in top yield of sugar beet between the studied harvesting dates. Top yield of sugar beet was gradually and significantly decrease with delaying the harvest date from 180 to 210 days of age. Similar results were obtained by Nour etal. (1973) and Mokadem (1999) and Mohamed (2002). They declared that the rapid building of the leaf constituents at such active stages of growth might account much for the latter observation. On the other hand, the loss in the weight of leaves at later stages might be mainly attributed to the death of leaves. Therefore, it can be observed that harvesting beet roots at 210 days of age had the lowest value of top yield.

With regard to sugar beet cultivars, the data given in Table (3) showed a significant difference among the studied four sugar beet cultivars in top yield (ton/fed.). the highest values of top yield was found in Gloria cultivar among the studied cultivars. This might be principally due to the genetic variation.

8.1.1.3. Recoverable sugar yield (ton/fed.)

It was evident from the results in Table (4 & 5) that sowing date of sugar beet had a significant effect on recoverable sugar yield at different harvesting dates and cultivars. Sowing sugar beet on 15th October increased by 3.76 and 28.97 compared with sowing on 15th September and November, respectively. Such data agree with those of Fadel (2002) who revealed that sowing sugar beet in the early and middle dates, i.e. 15th October significantly increased sugar yield. Here too, Nasr, (1992) reported that sowing date markedly affected sugar yield (ton/fed.) and that the highest sugar yield was recorded by sowing sugar beet on 15th October. It can be concluded that sowing sugar beet on October and September is recommended for reducing the loss in root and sugar yields at harvest to minimum and enhancing income of grower.

Harvesting date had a significant effect with regard to this trait at different sowing dates and cultivars as shown in Tables (4 & 5). Recoverable sugar yield of sugar beet at 195 days of age was increased by 0.24 and 33.12% when harvested at 210 and 180 days of ages, respectively. The increase in recoverable sugar yield of sugar beet when beet roots harvested at 195 days of age than the other harvesting dates especially 180 days of age may be attributed to an increase of dry matter accumulated in the roots. While, the slightly reduction in this trait when beet roots harvested at 210 days of age might be due to increasing sugar consumption in respiration and formation of new leaves. The findings recorded here in are in the same line with those studied by Besheit, (1986); Thomas (1996); El-Sayed, (1997) and Saif, etal. (1997) revealed that delaying harvest up to 210 days of age reduced sugar yield. Therefore, it could be reported that harvesting sugar beet at 195 days of age, but harvest must not delayed than 210 days of age is recommended for increasing sugar production and reducing the loss in recoverable sugar yield (ton/fed.) at harvest that carried out if the harvest earlied or delayed.

With regard to beet cultivars, the data obtained in Tables (4 & 5) demonstrated that a significant difference in this trait among the studied cultivars. Recoverable sugar yield of cultivars, i.e. Gloria and Oscar poly, was higher than cultivars, i.e. Allexa and Sofie. Recoverable sugar yield of Gloria cultivar increased by 5.53, 17.65 and 24.63% than Oscar poly, Allexa and Sofie cultivars, respectively. These results are in good agreement with those published by Azzazy, (1998); Abou-El.Magd (1998); El-Geddawy, etal. (2001) and Mohamed (2002) who stated that recoverable sugar yield of sugar beet was affected by three different factors: (1) Root yield (ton/fed.), (2) Percentage of sucrose content and (3) Percentage of impurities contents, i.e. alpha amino nitrogen, potassium and sodium contents. So, it could be pointed out that Gloria cultivar followed by Oscar poly is recommended for agriculture in El-Minia Governorate, for increasing income of grower and an increase of sugar production.