title: ggplot2 manually specifying colour with geom_line
body: <p>I'm trying to plot the graph below, and want to manually specify colours.</p>
  
  <p>I need to plot by genotype, since there are multiple genotypes belonging to the same Bgrnd_All, and I want them to come up separately in the lines plotted.</p>
  
  <p>However, I want to colour the lines by Bgrnd_All, and specifically in the order/colour I use in scale_fill_manual.</p>
  
  <p>When I do this, the values in scale_fill_manual do not overwrite the existing colour as defined in geom_line. How can I do this?</p>
  
  <p>I'd be grateful for pointers.</p>
  
  <p>[Data for graph below][1]<a href="https://www.dropbox.com/s/9nmu87wkh2yqfxn/summary_200_exp2.csv?dl=0" rel="noreferrer">https://www.dropbox.com/s/9nmu87wkh2yqfxn/summary_200_exp2.csv?dl=0</a></p>
  
  <pre><code>    pd &lt;- position_dodge(1)
  
  ggplot(data=summary.200.exp2, aes(x=Time, y=Length, colour=Genotype, group=Genotype)) + 
    geom_errorbar(aes(ymin=Length - se, ymax=Length + se), colour="black", width=1, position=pd) +
    geom_line(aes(colour=Bgrnd_All), position=pd, size =1) +
    scale_x_continuous(breaks=c(0,17,22,41,89)) + #using breaks of when sampled
    scale_fill_manual(values=c(Avalon="#000066",Av_A="#663399",Av_B="#339999",Cadenza="CC0033",Cad_A="FF6600",Cad_B="FF9933"))+
    ylab("leaf segment width (mm)") +
    xlab("Time") +
    theme(axis.title = element_text(size=14,face="bold"), 
          axis.text = element_text(size=14),
          strip.text.y = element_text(size=14))
  </code></pre>
  
  <hr>
  
  <p>A <code>dput</code> of the data:</p>
  
  <pre><code>summary.200.exp2 &lt;- structure(list(X = 1:40,
                                 Genotype = structure(c(1L, 1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L, 2L, 3L, 3L, 3L, 3L, 3L, 4L, 4L, 4L, 4L, 4L, 5L, 5L, 5L, 5L, 5L, 6L, 6L, 6L, 6L, 6L, 7L, 7L, 7L, 7L, 7L, 8L, 8L, 8L, 8L, 8L), .Label = c("4.18", "4.41", "7.50", "7.59", "8.51", "8.77", "Avalon", "Cadenza"), class = "factor"), 
                                 Time = c(0L, 17L, 22L, 41L, 89L, 0L, 17L, 22L, 41L, 89L, 0L, 17L, 22L, 41L, 89L, 0L, 17L, 22L, 41L, 89L, 0L, 17L, 22L, 41L, 89L, 0L, 17L, 22L, 41L, 89L, 0L, 17L, 22L, 41L, 89L, 0L, 17L, 22L, 41L, 89L), 
                                 Bgrnd_All = structure(c(4L, 4L, 4L, 4L, 4L, 5L, 5L, 5L, 5L, 5L, 1L, 1L, 1L, 1L, 1L, 2L, 2L, 2L, 2L, 2L, 5L, 5L, 5L, 5L, 5L, 4L, 4L, 4L, 4L, 4L, 3L, 3L, 3L, 3L, 3L, 6L, 6L, 6L, 6L, 6L), .Label = c("Av_A", "Av_B", "Avalon", "Cad_A", "Cad_B", "Cadenza"), class = "factor"), 
                                 N = c(43L, 48L, 44L, 47L, 48L, 22L, 21L, 26L, 27L, 25L, 36L, 24L, 44L, 48L, 45L, 50L, 26L, 52L, 54L, 53L, 38L, 52L, 52L, 49L, 50L, 39L, 39L, 42L, 38L, 42L, 84L, 42L, 84L, 42L, 42L, 50L, 26L, 53L, 27L, 27L), 
                                 Length = c(1.17423255813953, 1.58852083333333, 1.71263636363636, 1.86736170212766, 2.0331875, 1.07563636363636, 1.49866666666667, 1.48734615384615, 1.66796296296296, 2.15416, 1.08716666666667, 1.09858333333333, 1.24593181818182, 1.30827083333333, 1.81537777777778, 1.15672, 1.8475, 1.96815384615385, 2.01822222222222, 2.5057358490566, 1.14697368421053, 1.40276923076923, 1.49832692307692, 1.76981632653061, 2.27954, 1.18312820512821, 1.75928205128205, 1.86195238095238, 1.91426315789474, 2.26883333333333, 1.10839285714286, 1.97902380952381, 2.03271428571429, 2.15685714285714, 2.8227380952381, 1.08658, 1.68880769230769, 1.7277358490566, 1.9232962962963, 2.13466666666667), 
                                 sd = c(0.218740641945063, 0.357307960001092, 0.377931031662453, 0.416137123383518, 0.440003996899158, 0.176915784499843, 0.426273190962478, 0.305677731254037, 0.450036449932454, 0.48642939535627, 0.15212823538055, 0.175160775008132, 0.293836087650785, 0.282464815326021, 0.346608194369436, 0.211422397593258, 0.408328617659845, 0.413460118977535, 0.419730221832425, 0.508692484972064, 0.217587942685885, 0.207510416973071, 0.245473270071832, 0.377310585673427, 0.536134471785516, 0.159925670150259, 0.298319411009668, 0.338847829173593, 0.296186727462412, 0.445638589029855, 0.162594700328365, 0.308723610551514, 0.318831396748337, 0.381781291715339, 0.402059458017902, 0.167826451905484, 0.257140275994371, 0.338637947743116, 0.362428434825926, 0.343680867174096), 
                                 se = c(0.0333576351702583, 0.0515729617225566, 0.0569752467571038, 0.0606998379642952, 0.06350910651356, 0.0377185719899813, 0.0930204363959963, 0.0599483352513503, 0.0866095551712153, 0.097285879071254, 0.0253547058967583, 0.0357545434766975, 0.0442974569365289, 0.040770284291269, 0.0516692989445678, 0.0298996422065822, 0.0800798303617661, 0.0573366022820362, 0.0571180485063685, 0.0698742866122227, 0.0352974252834232, 0.0287765172534354, 0.0340410177692235, 0.053901512239061, 0.0758208641254813, 0.0256086023072023, 0.0477693365291991, 0.052285355168868, 0.0480478318490224, 0.0687635271596866, 0.0177405362346046, 0.0476370873204908, 0.0347873573697084, 0.0589101322645314, 0.0620391212561054, 0.0237342444409691, 0.0504293571163821, 0.046515499476421, 0.0697493848029077, 0.0661414137260961), 
                                 ci = c(0.0673184331863912, 0.103751416510302, 0.114901535684132, 0.122182436693452, 0.127763842564108, 0.0784400645137227, 0.194037230170767, 0.123465907623535, 0.178028490322197, 0.200788185881879, 0.0514727894594648, 0.0739639084701291, 0.0893343358495282, 0.0820192326650262, 0.104132629687123, 0.0600855805773719, 0.164927497928001, 0.11510803218647, 0.11456429705202, 0.140213013986381, 0.0715193770736051, 0.0577712690042106, 0.0683401947985261, 0.108376253996364, 0.152367731004308, 0.0518419050566429, 0.0967039660836575, 0.105592416917608, 0.0973541547573791, 0.138870760371045, 0.0352852130493688, 0.0962050495562246, 0.06919065466693, 0.118971425682342, 0.125290547146885, 0.0476957499005439, 0.103861205171753, 0.0933401784102089, 0.143371913789607, 0.135955623027448)), 
                            .Names = c("X", "Genotype", "Time", "Bgrnd_All", "N", "Length", "sd", "se", "ci"), class = "data.frame", row.names = c(NA, -40L))
  </code></pre>