Variety 5 Variety 5 days after infection 7 days after infection Harmful
3.3. Effect of some cultivation techniques for Bph-resistant rice varieties in Thua Thien Hue Through testing in the laboratory and in the field, along with the results of the analysis of
experimental rice quality, we found the variety HP28 has the highest resistance to Bph, and has good
yield, quality. Based on this result, we decided to choose the variety HP28 in order to identify and research appropriate farming techniques to propose the use of fertilizers guideline and suitable planting density for this Bph-resistant rice varieties
3.3.1. Effects of sowing density on the growth, development, yield and pest status of rice HP28 3.3.1.1. Effects of sowing density to a number of morphological criteria HP28 rice in Huong Tra, Thua Thien Hue
We found that when the sowing density increased, plant height tended to decrease; the reason of this difference is that changes in the density lead to competition for nutrients, light mode of individuals in different populations.
On the rice-paddies length and number of leaves on a tree in the experimental formula in both the winter-spring and the summer-autumn, the rice-paddies length fluctuated from 15.47 cm to 16.80 cm; a number of leaves on trees ranged from 9.30 cm to 9.93 cm, from that results, we evaluate that on the rice- paddies length and number of leaves on plants depend on genetic characteristics, were little changed.
3.3.1.2.The effect of sowing density on the tillering ability of HP28 in Huong Tra, Thua Thien Hue Overall, on all of experimental formulas of tillering ability of rice are inversely proportional to the density of sowing, when sowing density increasing, the tillering ability of the experimental formulas gradually reduced. On the effective number of branches is similar, the highest one is in the sowing formula 40kg/ha and the lowest is in the sowing formula 60 and 70 kg / ha, this issue in accordance with the general rule is the more sparse sowing is, the more ability tillering capacity has in comparation with thick sowing.
Table 3.18. Effect of sowing density on tillering ability of HP28 at Huong Tra Sowing
density (kg/ha)
The number of initial
branch (branch)
Total of branches
(branch)
Number of effective
branch (branch)
Tillering coefficient
(time)
Effective branching
ratio (%) Winter-Spring season
40 1 8,43a 5,40a 8,43 64,06
50 1 8,16ab 5,26ab 8,16 64,46
60 1 8,06ab 5,03bc 8,06 62,41
70 1 7,96b 4,80c 7,96 60,30
Summer-Autumn season
40 1 8,63a 5,26a 8,63 60,95
50 1 6,40b 5,00b 6,40 78,13
60 1 8,16bc 4,86bc 8,16 59,56
70 1 7,83c 4,70c 7,83 60,03
3.3.1.3. Effects of sowing density on Bph density changes on HP28 in Huong Tra, Thua Thien Hue
a. Effects of sowing density on BPH density developments in Huong Tra in Winter-Spring 2011 - 2012
From Figure 3.8 we find that on the different experimental formulas, the density of harmful Bph are also very different. Formula with 70kg sowed seeds / ha has the highest harmful Bph density
(72.3shrimp/m2), formula sowing with 60 kg / ha has the lowest harmful Bph density (54.0 units / m2), this can be explained as follows:
Formula with 70kg sow seeds / ha, sowing thick density makes rice growth, abnormal development, due to competition for light and nutrients, disable high tillering was favorable for BPH sting , lay eggs and cause harm incurred. The sowing formula of 40; 50 and 60 kg / ha, with little or medium planting rice density created to facilitate the development, balance leading to limit the damage caused by BPH. Through experimental results, we found that HP28 Bph resistant varieties, sowing density with 60kg/ha have the ability to limit the damage of Bph in the field.
In the summer-autumn crop in Huong Tra, the highest BPh density is on 70 kg / ha formula (8.33/m2) and the lowest density is on 60kg/ha formula (5.67/m2).
3.3.1.4. Effects of sowing density on the yield components and yield of the variety HP28 in Huong Tra
When increasing the number of seed from 40kg/ha to 70kg/ha, the number of flower tends to increase. This suggests that the sowing density is too high or too many … on clusters, some less flowers and rice grain may be small, besides seeding density is too high will lead to nutrient competition which cause the high rate of empty glumes, ultimately leads to reduced productivity.
Sowing density is too high (70kg/ha) has reduced the number of grains on riceflower, the density of the remaining 40; 50; 60 kg / ha on riceflower has the number of firm rice grains is equivalent.
Table 3.21. Effect of sowing density on the yield components and yield of BPH rice varieties HP28 in Huong Tra
Targets Winter-Spring season Summer-Autumn season
40kg/ha 50kg/ha 60kg/ha 70kg/ha 40kg/ha 50kg/ha 60kg/ha 70kg/ha panicle/m2 350,67c 382,00b 390,00b 409,33a 350,33b 369,67b 418,00a 424,67a Number of grain
/panicle(grain) 78,80a 78,47a 81,00a 72,47b 87,03a 87,37a 78,80a 66,90b Grain
solid/bông(hạt) 70,30a 69,10a 70,20a 52,70b 69,93a 71,67a 61,86b 48,26c P.1000grains (g) 24,70b 25,43a 25,63a 24,43b 24,40a 24,60a 24,40a 24,33a
Figure 3.8. BPH density on the density of sowing in winter- spring season 2011-2012 in Huong Tra Thua Thien Hue
Figure 3.9. BPH density on the density of sowing in summer-autumn season 2012 in Huong Tra Thua Thien Hue
Theoretical Yield 60,89c 67,13b 70,17a 52,70c 59,78c 65,18b 63,10a 49,87c Actual yield 41,38c 48,43b 51,96a 39,32d 40,70bc 43,95ab 47,30a 37,80c The highest actual yield in crop is 51.96 quintals / ha (60kg/ha), the lowest is 39.32 quintals / ha (70kg/ha). Similarly the highest one in the summer-autumn is 47.3 kg / ha (60kg/ha) and the lowest is 37.8 kg / ha (70kg/ha). This proves that the sowing density of Bph resistant variety HP28 with 60kg/ha has the highest actual yield.
3.3.1.5 Effects of sowing density to a number of morphological criteria HP28 rice in Phu Vang, Thua Thien Hue
The plant height target on all the experimental formulas tend to decrease, when increasing sowing density, the plant height reaches at highest with sowing formula of 40kg/ha .
On the different ground, the height of rice is different; the height of rice on alluvial soil in Huong Tra is taller than on sandy lagoons in Phu Vang. From there, we get to know that the tree height is affected by the nutrient elements in the soil, light and temperature. On the rice flower length, the number of leaves on the tree through all the experimental formulas had no significant difference because they depend largely on genetic factors.
3.3.1.6. Effect of sowing density on the ability of the tillering variety HP28 in Phu Vang, Thua Thien Hue
During the experimental formulas, sowing density with 40kg/ha have the highest number of effective branches, followed by density with 50; 60 kg / ha, the formula of 70kg/ha have the total number of branches and the lowest effective branch.
Table 3.23. Effect of sowing density on tillering ability of HP28 at Phu Vang
Sowing density (kg/ha)
The number of
initial branch (branch)
Total of branches
(branch)
Number of effective
branch (branch)
Tillering coefficient
(time)
Effective branching
ratio (%) Winter-Spring season
40 1 8,00b 5,40a 8,00 67,50
50 1 8,10a 5,10b 8,10 62,96
60 1 7,56c 4,76c 7,56 62,96
70 1 7,70bc 4,70c 7,70 61,04
Summer-Autumn season
40 1 8,33a 5,33a 8,33 63,99
50 1 6,43ab 5,03ab 6,43 78,23
60 1 8,03a 4,93b 8,03 61,39
70 1 7,86a 4,73b 7,86 60,18
3.3.1.7 Effects of sowing density on Bph density changes on HP28 in Phu Vang, Thua Thien Hue From the experimental results are presented in Figure 3.8; 3.9; 3:11; 3:12, we have the following comments:
BPH density in all experimental formulas in both the winter- spring and the summer-autumn in sandy areas along the lagoon, Phu Vang is higher in Huong Tra alluvial plain, which suggests that in Thua Thien Hue BPH causes heavy losses in arable land infertile.
In Thua Thien Hue, in the summer-autumn crop Bph arise and develop more severe damage in the winter-spring crop, which is perfectly consistent with the rule of the harm arising BPH. In the summer-autumn crop in Thua Thien Hue, high temperature (25 -300 C), relative humidity ranged between 60-80% is suitable conditions for developing BPH.
For the Bph resistant variety HP28, sowing density with 60kg/ha likely be limited BPH density field.
3.3.1.8. Effects of sowing density on the yield components and yield of the Bph resistant variety HP28in Phu Vang Thua Thien Hue
For the variety HP28, sowing density with 60kg/ha have yield components and actual yield which is the highest.
Table 3.26. Effect of sowing density on the yield components and yield of BPH rice varieties HP28 in Phu Vang
Targets Winter-Spring season Summer-Autumn season
40kg/ha 50kg/ha 60kg/ha 70kg/ha 40kg/ha 50kg/ha 60kg/ha 70kg/ha panicle/m2 349,33d 377,67c 388,67b 401,00a 342,33b 356,00b 405,00a 412,33a Number of grain
/panicle(grain) 80,87b 82,00b 87,53a 73,17c 85,33a 84,37a 78,63b 65,00c Grain
solid/bông(hạt) 68,33b 68,57b 72,37a 52,43c 68,10a 66,53ab 61,07b 48,30c P.1000grains (g) 25,30a 25,23a 24,80a 24,73a 25,47a 25,23a 25,13a 25,00a Theoretical Yield 60,39c 65,34b 69,67a 51,99d 59,38bc 59,76b 62,15a 49,79c Actual yield 40,98c 46,10b 50,21a 38,45c 40,07b 42,03b 46,25a 35,83c 3.3.2. Effects of fertilizer combination on the growth, development and yield of rice HP28
The determination of the effect of fertilizer combinations on yield and Bph-resistant variety of HP28 in Winter-Spring 2012-2013 Summer-Autumn 2013 in Thua Thien Hue is presented below:
Figure 3.11. BPH density on the density of sowing in
winter-spring season 2011-2012 in Phu Vang Thua Figure 3.12. BPH density on the density of sowing in summer-autumn season 2012 in Phu Vang Thua Thien
3.3.2.1. Effects of fertilizer formula on tree height through the growth stages of rice HP28
When nitrogen has been manured and amount of potassium has been increased at the same time, the plan height difference between the recipes is very few in both experiments for the winter- spring and summer-autumn crop. Thus, through the above data, we found that rice plant height is less affected by potassium.
The quantity of potassium is same while the quantity of nitrogen is increased; plant height of the formulas had difference between the formulations especially in summer-autumn crop and fertilizer at 150N. Increased nitrogen fertilizer, plant growth height of the nitrogen formula significantly increased in all 3 periods, higher nitrogen fertilizer, and plant height increases. Thus, the protein has a very important role in the growth of rice plant height.
In summary, the plant height has been enormously affected by the quantity of fertilizer, especially nitrogen. In the alluvial plain Huong Tra, protein plays an important role in the growth of plant height; potassium does not seem to significantly influence on the height in this area. However, in the sandy area along the lagoon, Phu Vang, a combination of nitrogen and potassium is effective in promoting high height of rice plants resistant to Bph. When manuring combinatively 150N/100K2O, the tree height increased most clearly.
When nitrogen is retained, and potassium fertilizer increased, we found that the maximum number of branches and number of branches increased only effective fertilizer at 150K. When potassium fertilizers is constant that increased protein intake, number of effective branches of the formulas differ little. The number of effective branches across 2 seasons at the fertilizer 150N is highest.
3.3.2.2. Effects of fertilizer formula to the tillering ability of the variety HP28
The maximum number of branches and number of effective branches are increased proportional to the amount of nitrogen and potassium fertilizers in the two crops, reaching the highest tributaries effectively fertilizer at 150N/100K.
Thus, protein and potassium play a major role in the tillering of rice. When nitrogen and potassium was fertilized at 150N/100K level which usually produce the highest number of effective branches especially in summer-autumn crop.
Figure 3.14. Effect of fertilizer combination for tillering ability of BPH resistant varieties HP28 in
Huong Tra, Thua Thien Hue
Figure 3.15. Effect of fertilizer combination for tillering ability of BPH resistant varieties HP28 in
Phu Vang, Thua Thien Hue
On the effective number of branches: we can see that for the variety HP28 resistant to Bph, the quantity of 150N/90P/120K fertilizer have maximum number of branches and the highest number of effective branches in the research both in Huong Tra and Phu Vang in winter-spring and summer- autumn crops.
3.3.2.3. Effects of fertilizer formula to density of brown hoppers with rice HP28
According to results of brown hoppers’density development in experimental formula in Winter-Spring crop 2012-2013 in the experimental field in Huong Tra, there are 2 formulas in which the density of brown hoppers is lower 90N/100K and 120N/80K than control formula. This indicates nitrogen fertilizing rates proportional to the severity of BPH (Figure3:16).
And in experimental formulas in Summer-Autumn crop 2013 in Huong Tra experimental field, Thua Thien Hue province: quantity of fertilizer has affected the ability to anti brown hoppers of rice HP28, fertilize with high quantity of nitrogen and potassium has risen brown hoppers’density (Figure 3:17).
Results of research on the density of brown hoppers in the winter-spring 2012-2013 in sandy area along the lagoon (Phu Vang) show that:
The quantity of fertilizer has affected the number of brown hoppers in fields, fertilize rice with too high or too low quantity of nitrogen will increase brown hoppers’ density. In our experiment, the proportion 100N/100K in 90P foundation will be the best to anti pest.
Figure 3.16. Effect of fertilizer combination for BPH density in winter-spring in Huong Tra, Thua
Thien Hue
Figure 3.17. Effect of fertilizer combination for BPH density in summer-autumn in Huong Tra,
Thua Thien Hue
Figure 3.18. Effect of fertilizer combination for BPH density in winter-spring in Phu Vang, Thua
Thien Hue
Figure 3.19. Effect of fertilizer combination for BPH density in summer-autumn in Phu Vang, Thua
Thien Hue
Besides investigating brown hoppers’density on experimental formulas in Phu Vang in the Summer-Autumn crop, we inquired brown hoppers’ density in winter-spring 2013, results were showed in Figure.3.19. We can see that both nitrogen and potassium affect brown pest’s density in Summer-Autumn crop in Phu Vang, and the proportion 120N/100K is the best amount of fertilizer which increases rice HP28’s ability against BPH.
3.3.2.4. Effects of formula of fertilizer on yield and yield components of rice HP28
Productivity in theory: there are 3 formulas higher than the control formula: 90N/100K, 120N/100K and 150N/100K. Actual yield: there are 2 formulas higher than the control formula:
90N/100K (47 kg / ha in the spring and the 45,6 kg / ha in summer-autumn crop), 150N/80K (45,2 kg/ha in the spring and the 44,8 kg / ha in summer-autumn crop). In particular, the actual productivity of the formula 90N/100K is the highest.
Besides the inherent yield potential of the rice variety, aphids are a factor that has a big effect on rice productivity (the formula 90N/100K is less infected by pest, so it has higher productivity).
One of the reasons of pest development is the amount of fertilizers applied in experimental formulas. Whereas, the formula 150N/100K makes it the most convenient for pest to develop, 90N/100K has the lowest amount of pest.
Concerning the productivity in theory,formulas whose nitrogen is 100K higher than the control formula. The highest is 90N/100K (58,7 kg / ha). The rest have theoretical productivity lower than the control formula. Concerning actual yield, there are 2 formulas higher than the control formula: 120N /80K (46,57 kg / ha in Winter-Spring crop and 44,87 kg / ha in Summer-Autumn crop) and 150N /100K (45,4 kg / ha in Winter-Spring crop and 43,8 kg / ha in the Summer-Autumn crop)
Table 3.35. Effect of fertilizer combination for yield components and yield of BPH rice varieties HP28 in Huong Tra
Targets CT1 CT2 CT3 CT4 CT5 CT6
Winter-Spring season
panicle/m2 352,00c 409,30a 339,00c 336,00c 351,00c 375,00b
Number of grain
/panicle(grain) 83,40bc 87,50a 78,70d 85,40abc 81,40cd 86,70abc Grain solid/bông(hạt) 62,60bc 69,90a 57,80c 66,40ab 63,70abc 64,20bc
P.1000grains (g) 25,40 25,60 25,60 25,20 25,30 25,50
Theoretical Yield (ta/ha) 56,00bc 73,20a 50,20c 58,90b 55,40bc 58,30c Actual yield (ta/ha) 42,60bc 47,00a 40,70c 43,30abc 45,20ab 41,10c
Summer-Autumn season
panicle/m2 331,00c 382,30ab 320,30d 376,00b 327,00cd 389,30a Number of grain
/panicle(grain) 83,90ab 87,70a 81,60b 85,20ab 83,50ab 86,20ab Grain solid/bông(hạt) 63,50ab 67,20a 58,60b 66,40a 63,60ab 61,30ab
P.1000grains (g) 25,50 25,70 25,60 25,10 25,30 25,60
Theoretical Yield (ta/ha) 53,70b 66,10a 48,00c 62,70a 52,60bc 61,10a Actual yield (ta/ha) 44,40ab 45,60a 40,70c 44,40ab 44,80ab 42,60bc
Table 3.36. Effect of fertilizer combination for yield components and yield of BPH rice varieties HP28 in Phu vang
Targets CT1 CT2 CT3 CT4 CT5 CT6
Winter-Spring season
panicle/m2 338,73bc 384,53a 322,9c 354,53b 353,77b 342,27b Number of grain
/panicle(grain) 82b 84,57a 81,87b 80,33c 81,93b 81,47b Grain solid/bông(hạt) 60,97c 65,13a 63,37b 62,77b 61,8c 62,73b P.1000grains (g) 24,27a 23,43a 23,5a 23,77a 24,1a 24,2a Theoretical Yield
(ta/ha) 50,08bc 58,7a 48,07c 52,9b 52,71b 51,96bc
Actual yield (ta/ha) 43,7cd 42,63d 46,57a 44,33bc 44,67bc 45,4ab Summer-Autumn season
panicle/m2 330,93c 364,57a 321,83c 349,03b 348,8b 348,8b Number of grain
/panicle(grain) 81,2b 83,17a 81,03b 79,2c 81,43b 81,43b Grain solid/bông(hạt) 60,63d 62,4a 63,07ab 61,4cd 61,17cd 61,17bc P.1000grains (g) 23,07b 22,57b 22,03b 23,13ab 23,17ab 23,17a Theoretical Yield
(ta/ha) 46,28bc 52,58a 44,73c 49,59ab 49,45ab 49,45a
Actual yield (ta/ha) 43,03bc 42,3c 44,87a 43,9b 43,8b 43,8a
3.3.2.5. Effects of fertilizer’s combinations on some soil chemical properties after experiment:
To investigate effects of dose of nitrogen and potassium on agricultural targets of soil, we have analysed some basic criteria agricuture before and after the experiment in the formulas.
- Soil acidity (pHKCl): From results collected, we found that fertilizer reduced acidity of soil a little bit than before the experiment.
Table 3.37. Effect of fertilizer combination to some soil chemistry experiment in Huong Tra, Thua Thien Hue
Formula pH (Kcl) OC (%) N (%) P2O5 (%) K2O (%)
Previous experiment 4,09 1,59 0,071 0,045 0,55
After experiment
90N-90P-80K 4,01 1,66 0,074 0,048 0,56
90N- 90P-100K 3,99 1,68 0,074 0,047 0,61
120N-90P-80K 4,17 1,77 0,076 0,042 0,61
120N-90P-100K 4,04 1,73 0,081 0,049 0,65
150N-90P-80K 4,02 1,74 0,08 0,05 0,58
150N-90P-100K 4,09 1,74 0,083 0,059 0,68
- Content of organic matter in the soil (OC%): The result of the analysis showed that after testing organic matter’s content in the soil in all formulations was significantly increased, the highest
levels of organic matter in the soil reaches 1.77% in Huong Tra (120N + 80k) and 1.60% in Phu Vang (150N). This proves fertilizer affects the accumulation of organic matter in the soil.
Table 3.38. Effect of fertilizer combination to some soil chemistry experiment in Phu vang, Thua Thien Hue
Formula
pH (Kcl) OC (%) N (%) P2O5 (%) K2O (%)
Previous experiment 4,500 1,390 0,056 0,023 0,400
After experiment
90N-90P-80K 4,320 1,390 0,061 0,029 0,450
90N- 90P-100K 4,470 1,430 0,063 0,034 0,490
120N-90P-80K 4,540 1,560 0,069 0,033 0,470
120N-90P-100K 4,420 1,560 0,065 0,037 0,500
150N-90P-80K 4,580 1,600 0,071 0,034 0,470
150N -90P-100K 4,400 1,600 0,071 0,037 0,520
-Total content of nitrogen (N%): In general, total content of nitrogen in the soil in both the two experimental areas is low. It can be concluded that these areas are infertile lands. After experiment, total content of nitrogen in formulations tends to gradually increase following different dose of fertilizer.
- Total content of phosphorus (P2O5%): Total content of phosphorus in formulations is different, this proves P2O5 content in the soil is changed by applying other fertilizers such as N and K2O.
- Total content of potassium (K2O%): Results of the analysis showed that the total potassium content in the soil of the formula before and after the experiment were low to moderate. Total potassium content in the soil after the experiment increased as compared to the soil before the experiment. Especially in the fertilizing formulas which have higher content of potassium, total potassium content in the soil after the experiment is higher.
CONCLUSIONS AND SUGGEST 1. Conclusions
1.1. Mudgo (Bph1 resistance gene) expression BPH infection, ASD7 (bph2 resistance gene) and Babawee (bph4 resistance gene) exhibit resistance, Rathu Heenati (Bph3 resistance gene) and PTB33 (bph2 and Bph3 resistance gene) exhibit moderate resistance for BPH in Thua Thien Hue, which determine biotype of BPH populations in Thua Thien Hue primarily belong to biotype 2.
1.2. Among 61 evaluated varieties, 14 varieties (HP01, HP04, HP05, HP06, HP07, HP10, HP19, HP28, HP29, G8, G11, G19, RNT07, RNT03) had expressed moderately resistance to BPH population at Thua Thien Hue in the laboratory.
1.3. Identifying the presence of resistance gene showed that most varieties expressing BPH resistance in the laboratory had BPH resistance genes (Bph1, bph2 and Bph3). Therefore, these varieties are tightly linked with resistance genes Bph1, bph2 and Bph3.
1.4. The most varieties expressing BPH resistance in the laboratory are capable of well growth, high yield, good quality and the high capacity BPH resistance at Thua Thien Hue. In
particular, three varieties HP07, HP10, HP28 expression highest capacity BPH resistance. 1.5. Các giống lúa được chọn lọc (HP01, HP05, HP07, HP10, HP19, HP28, HP29, RNT07) đều có phẩm chất gạo tốt, đáp ứng được nhu cầu thị hiếu của người tiêu dùng.
1.6. For Thua Thien Hue the results have identified at seed volume of 60kg/ha and the fertilizer combination with 120kg N - 90kgP2O5 - 100kg K2O – 500kg lime – 10 tons of farm yard manure/ha obtained the highest yield, soil fertility improvement and the highest capacity BPH resistance for varieties HP28 in two growing seasons (spring- winter and autumn-summer) at Thua Thien Hue.