Search

Producción Científica, Unmanned Aerial Vehicles (UAVs) offer excellent survey capabilities at low cost to provide farmers with information about the type and distribution of weeds in their fields. In this study, the problem of detecting the infestation of a typical weed (charlock mustard) in an alfalfa crop has been addressed using conventional digital cameras installed on a lightweight UAV to compare RGB-based indices with the widely used Normalized Difference Vegetation Index (NDVI) index. The simple (R−B)/(R+B) and (R−B)/(R+B+G) vegetation indices allowed one to easily discern the yellow weed from the green crop. Moreover, they avoided the potential confusion of weeds with soil observed for the NDVI index. The small overestimation detected in the weed identification when the RGB indices were used could be easily reduced by using them in conjunction with NDVI. The proposed methodology may be used in the generation of weed cover maps for alfalfa, which may then be translated into site-specific herbicide treatment maps., Unión Europea (project LIFE11 ENV/ES/000535)

Producción Científica, Unmanned Aerial Vehicles (UAVs) offer excellent survey capabilities at low cost to provide farmers with information about the type and distribution of weeds in their fields. In this study, the problem of detecting the infestation of a typical weed (charlock mustard) in an alfalfa crop has been addressed using conventional digital cameras installed on a lightweight UAV to compare RGB-based indices with the widely used Normalized Difference Vegetation Index (NDVI) index. The simple (R−B)/(R+B) and (R−B)/(R+B+G) vegetation indices allowed one to easily discern the yellow weed from the green crop. Moreover, they avoided the potential confusion of weeds with soil observed for the NDVI index. The small overestimation detected in the weed identification when the RGB indices were used could be easily reduced by using them in conjunction with NDVI. The proposed methodology may be used in the generation of weed cover maps for alfalfa, which may then be translated into site-specific herbicide treatment maps., Unión Europea (project LIFE11 ENV/ES/000535)

Producción Científica, Unmanned Aerial Vehicles (UAVs) offer excellent survey capabilities at low cost to provide farmers with information about the type and distribution of weeds in their fields. In this study, the problem of detecting the infestation of a typical weed (charlock mustard) in an alfalfa crop has been addressed using conventional digital cameras installed on a lightweight UAV to compare RGB-based indices with the widely used Normalized Difference Vegetation Index (NDVI) index. The simple (R−B)/(R+B) and (R−B)/(R+B+G) vegetation indices allowed one to easily discern the yellow weed from the green crop. Moreover, they avoided the potential confusion of weeds with soil observed for the NDVI index. The small overestimation detected in the weed identification when the RGB indices were used could be easily reduced by using them in conjunction with NDVI. The proposed methodology may be used in the generation of weed cover maps for alfalfa, which may then be translated into site-specific herbicide treatment maps., Unión Europea (project LIFE11 ENV/ES/000535)

Producción Científica, Unmanned Aerial Vehicles (UAVs) offer excellent survey capabilities at low cost to provide farmers with information about the type and distribution of weeds in their fields. In this study, the problem of detecting the infestation of a typical weed (charlock mustard) in an alfalfa crop has been addressed using conventional digital cameras installed on a lightweight UAV to compare RGB-based indices with the widely used Normalized Difference Vegetation Index (NDVI) index. The simple (R−B)/(R+B) and (R−B)/(R+B+G) vegetation indices allowed one to easily discern the yellow weed from the green crop. Moreover, they avoided the potential confusion of weeds with soil observed for the NDVI index. The small overestimation detected in the weed identification when the RGB indices were used could be easily reduced by using them in conjunction with NDVI. The proposed methodology may be used in the generation of weed cover maps for alfalfa, which may then be translated into site-specific herbicide treatment maps., Unión Europea (project LIFE11 ENV/ES/000535)

The rapeseed (Brassica napus var. napus L.) is grown for seeds that contain 40-48% oil and 18-25% protein. The oil is high quality and it can be used for food. In our country, rapeseed oil is produced primarily for biodiesel. As with other crops, yield reduction may be caused by climatic factors and agricultural practices including a belated control of weeds, insects and phytopathogenic fungi. The wild mustard (Sinapis arvensis) is the major weed in the rapeseed, mostly because it comes from the same family and has similar genetic background as the rapeseed. The wild mustard causes multiple negative effects in rapeseed crop. The high content of erucic acid in mustard seed impairs oil quality, and the cake cannot be used as animal feed because of the presence of glucosinolates. Such oil renders low-quality biodiesel. Most herbicides are ineffective in the control of wild mustard in rapeseed crop. The rapeseed is also attacked by a large number of insect pests. Major pests in the fall are the cabbage stem flea beetle (Psylliodes chrysocephala) and the turnip sawfly (Athalia rosae). Both species may cause total damage. Major pests in the spring are the common pollen beetle (Meligethes aeneus) and weevils (Ceutorhynchus spp.). It has been reported that the activity of pollen beetle imagoes and larvae may reduce rapeseed yield up to 50%. One or more chemical treatments are needed to effectively control this pest. Second and third treatments may cause problems because they coincide with high activity of sensitive pollinating insects. Currently, the major phytopathogenic fungi are Sclerotinia sclerotiorum, Phoma lingam and Peronospora parasitica. The above pests are present in all rapeseed-growing regions. Although the damages caused so far have been negligible, the increasing frequency of pest occurrence seems to indicate that these pests may pose serious problems in rapeseed production in coming years., Uljana repica (Brassica napus var. napus L.) se gaji radi semena koje sadrži 40-48% ulja i 18-25% belančevina. Ulje je visokog kvaliteta te se može koristiti i za ishranu ljudi. Proizvodnja biodizela iz repičinog ulja predstavlja osnovni razlog gajenja ove kulture u našoj zemlji. Kao i kod drugih biljnih vrsta smanjenje prinosa, pored klimatskih faktora i agrotehničkih mera, može biti izazvano i neblagovremenom zaštitom (suzbijanje korova, insekata i fitopatogenih gljiva). Od korovskih vrsta najveći problem predstavlja Sinapis arvensis (gorušica). Problem se ogleda u tome što je navedenu korovsku vrstu teško suzbiti (agrotehničke i hemijske mere) jer pripada istoj familiji kao i uljana repica. Od fitopatogenih gljiva za sada su najznačajnije Sclerotinia sclerotiorum, Phoma lingam i Peronospora parasitica. Navedeni paraziti u povoljnim klimatskim uslovima mogu izazvati oboljenja na biljkama uljane repice. Na ovoj biljnoj vrsti štete pričinjavaju i insekti. U najznačajnije spadaju buvači, repičina lisna osa i repičin sjajnik.

Pollination is one of the most important factors determining the reproductive success of plants. This thesis examines processes associated to varying pollination, with focus on plant responses. The first aim was to examine the possibility and constraints for short-term evolution of flower size in Raphanus raphanistrum. The results showed that there exists a possibility for pollinator-mediated short-term evolution of flower size in the study species. Flower size was strongly correlated to plant size. Since flower size cannot evolve separately from plant size, this correlation may constitute a constraint to the evolution of flower size. The second aim was to determine how varying pollen load affects later flowering, reproduction and growth of maternal plants. High pollen load treatment resulted in larger or more flowers on late flowers, which may enhance pollen dispersal and reproductive success, while the total seed mass was the same between treatments. The results indicate that the study species R. raphanistrum, Sinapis arvensis and Brassica napus have plastic responses in floral traits according to the present pollination level. The third aim was to determine how varying pollen load affects seed quality and offspring vigor. The results suggest that high pollen load had no positive effects on seed quality or offspring vigor due to pollen competition. Instead, seed mass determined seed quality and offspring vigor in the three study species and low pollen load treatment resulted in highquality offspring due to heavier seeds. The fourth aim was to examine causes and consequences of variation in reproductive success of Succisa pratensis on a regional scale. The results suggest that the most important variables, on a regional scale, for reproductive success were population size and habitat quality. The results showed that seed weight variation might be important when assessing reproductive success. In this study, seed weight variation did not seem to be adaptive.

Pollination is one of the most important factors determining the reproductive success of plants. This thesis examines processes associated to varying pollination, with focus on plant responses. The first aim was to examine the possibility and constraints for short-term evolution of flower size in Raphanus raphanistrum. The results showed that there exists a possibility for pollinator-mediated short-term evolution of flower size in the study species. Flower size was strongly correlated to plant size. Since flower size cannot evolve separately from plant size, this correlation may constitute a constraint to the evolution of flower size. The second aim was to determine how varying pollen load affects later flowering, reproduction and growth of maternal plants. High pollen load treatment resulted in larger or more flowers on late flowers, which may enhance pollen dispersal and reproductive success, while the total seed mass was the same between treatments. The results indicate that the study species R. raphanistrum, Sinapis arvensis and Brassica napus have plastic responses in floral traits according to the present pollination level. The third aim was to determine how varying pollen load affects seed quality and offspring vigor. The results suggest that high pollen load had no positive effects on seed quality or offspring vigor due to pollen competition. Instead, seed mass determined seed quality and offspring vigor in the three study species and low pollen load treatment resulted in highquality offspring due to heavier seeds. The fourth aim was to examine causes and consequences of variation in reproductive success of Succisa pratensis on a regional scale. The results suggest that the most important variables, on a regional scale, for reproductive success were population size and habitat quality. The results showed that seed weight variation might be important when assessing reproductive success. In this study, seed weight variation did not seem to be adaptive.

Pollination is one of the most important factors determining the reproductive success of plants. This thesis examines processes associated to varying pollination, with focus on plant responses. The first aim was to examine the possibility and constraints for short-term evolution of flower size in Raphanus raphanistrum. The results showed that there exists a possibility for pollinator-mediated short-term evolution of flower size in the study species. Flower size was strongly correlated to plant size. Since flower size cannot evolve separately from plant size, this correlation may constitute a constraint to the evolution of flower size. The second aim was to determine how varying pollen load affects later flowering, reproduction and growth of maternal plants. High pollen load treatment resulted in larger or more flowers on late flowers, which may enhance pollen dispersal and reproductive success, while the total seed mass was the same between treatments. The results indicate that the study species R. raphanistrum, Sinapis arvensis and Brassica napus have plastic responses in floral traits according to the present pollination level. The third aim was to determine how varying pollen load affects seed quality and offspring vigor. The results suggest that high pollen load had no positive effects on seed quality or offspring vigor due to pollen competition. Instead, seed mass determined seed quality and offspring vigor in the three study species and low pollen load treatment resulted in highquality offspring due to heavier seeds. The fourth aim was to examine causes and consequences of variation in reproductive success of Succisa pratensis on a regional scale. The results suggest that the most important variables, on a regional scale, for reproductive success were population size and habitat quality. The results showed that seed weight variation might be important when assessing reproductive success. In this study, seed weight variation did not seem to be adaptive.

Pollination is one of the most important factors determining the reproductive success of plants. This thesis examines processes associated to varying pollination, with focus on plant responses. The first aim was to examine the possibility and constraints for short-term evolution of flower size in Raphanus raphanistrum. The results showed that there exists a possibility for pollinator-mediated short-term evolution of flower size in the study species. Flower size was strongly correlated to plant size. Since flower size cannot evolve separately from plant size, this correlation may constitute a constraint to the evolution of flower size. The second aim was to determine how varying pollen load affects later flowering, reproduction and growth of maternal plants. High pollen load treatment resulted in larger or more flowers on late flowers, which may enhance pollen dispersal and reproductive success, while the total seed mass was the same between treatments. The results indicate that the study species R. raphanistrum, Sinapis arvensis and Brassica napus have plastic responses in floral traits according to the present pollination level. The third aim was to determine how varying pollen load affects seed quality and offspring vigor. The results suggest that high pollen load had no positive effects on seed quality or offspring vigor due to pollen competition. Instead, seed mass determined seed quality and offspring vigor in the three study species and low pollen load treatment resulted in highquality offspring due to heavier seeds. The fourth aim was to examine causes and consequences of variation in reproductive success of Succisa pratensis on a regional scale. The results suggest that the most important variables, on a regional scale, for reproductive success were population size and habitat quality. The results showed that seed weight variation might be important when assessing reproductive success. In this study, seed weight variation did not seem to be adaptive.

Pollination is one of the most important factors determining the reproductive success of plants. This thesis examines processes associated to varying pollination, with focus on plant responses. The first aim was to examine the possibility and constraints for short-term evolution of flower size in Raphanus raphanistrum. The results showed that there exists a possibility for pollinator-mediated short-term evolution of flower size in the study species. Flower size was strongly correlated to plant size. Since flower size cannot evolve separately from plant size, this correlation may constitute a constraint to the evolution of flower size. The second aim was to determine how varying pollen load affects later flowering, reproduction and growth of maternal plants. High pollen load treatment resulted in larger or more flowers on late flowers, which may enhance pollen dispersal and reproductive success, while the total seed mass was the same between treatments. The results indicate that the study species R. raphanistrum, Sinapis arvensis and Brassica napus have plastic responses in floral traits according to the present pollination level. The third aim was to determine how varying pollen load affects seed quality and offspring vigor. The results suggest that high pollen load had no positive effects on seed quality or offspring vigor due to pollen competition. Instead, seed mass determined seed quality and offspring vigor in the three study species and low pollen load treatment resulted in highquality offspring due to heavier seeds. The fourth aim was to examine causes and consequences of variation in reproductive success of Succisa pratensis on a regional scale. The results suggest that the most important variables, on a regional scale, for reproductive success were population size and habitat quality. The results showed that seed weight variation might be important when assessing reproductive success. In this study, seed weight variation did not seem to be adaptive.

Pollination is one of the most important factors determining the reproductive success of plants. This thesis examines processes associated to varying pollination, with focus on plant responses. The first aim was to examine the possibility and constraints for short-term evolution of flower size in Raphanus raphanistrum. The results showed that there exists a possibility for pollinator-mediated short-term evolution of flower size in the study species. Flower size was strongly correlated to plant size. Since flower size cannot evolve separately from plant size, this correlation may constitute a constraint to the evolution of flower size. The second aim was to determine how varying pollen load affects later flowering, reproduction and growth of maternal plants. High pollen load treatment resulted in larger or more flowers on late flowers, which may enhance pollen dispersal and reproductive success, while the total seed mass was the same between treatments. The results indicate that the study species R. raphanistrum, Sinapis arvensis and Brassica napus have plastic responses in floral traits according to the present pollination level. The third aim was to determine how varying pollen load affects seed quality and offspring vigor. The results suggest that high pollen load had no positive effects on seed quality or offspring vigor due to pollen competition. Instead, seed mass determined seed quality and offspring vigor in the three study species and low pollen load treatment resulted in highquality offspring due to heavier seeds. The fourth aim was to examine causes and consequences of variation in reproductive success of Succisa pratensis on a regional scale. The results suggest that the most important variables, on a regional scale, for reproductive success were population size and habitat quality. The results showed that seed weight variation might be important when assessing reproductive success. In this study, seed weight variation did not seem to be adaptive.