I have a dataset of >100 different samples. Samples are from different genotypes (e.g. X, Y, Z) and 4 different time points (T0,1,2,3) with 3 biological replicates (R1,2,3). I'm measuring values for 50 different genes (in raws)

       structure(list(Gene = structure(1:2, .Label = c("A", "B"), class = "factor"), X_T0_R1 = c(1.46559502, 0.220140568), X_T0_R2 = c(1.087642983, 0.237500819), X_T0_R3 = c(1.424945196, 0.21066267), X_T1_R1 = c(1.289943948, 0.207778662), X_T1_R2 = c(1.376535013, 0.488774258), X_T1_R3 = c(1.833390311, 0.182798731), X_T2_R1 = c(1.450753714, 0.247576125), X_T2_R2 = c(1.3094609, 0.390028842), X_T2_R3 = c(0.5953716, 1.007079177), X_T3_R1 = c(0.7906009, 0.730242116), X_T3_R2 = c(1.215333041, 1.012914813), X_T3_R3 = c(1.069312467, 0.780421013), Y_T0_R1 = c(0.053317766, 3.316414959), Y_T0_R2 = c(0.506623748, 3.599442788), Y_T0_R3 = c(0.713670106, 2.516735845), Y_T1_R1 = c(0.740998252, 1.444496448), Y_T1_R2 = c(0.648231834, 0.097957459), Y_T1_R3 = c(0.780499252, 0.187840968), Y_T2_R1 = c(0.35344654, 1.190274584), Y_T2_R2 = c(0.220223951, 1.367784148), Y_T2_R3 = c(0.432856978, 1.403057729), Y_T3_R1 = c(0.234963735, 1.232129062), Y_T3_R2 = c(0.353770497, 0.885122768), Y_T3_R3 = c(0.396091395, 1.333921747), Z_T0_R1 = c(0.398000559, 1.286528398), Z_T0_R2 = c(0.384759325, 1.122251177), Z_T0_R3 = c(1.582230097, 0.697419716), Z_T1_R1 = c(1.136843842, 0.804552001), Z_T1_R2 = c(1.275683837, 1.227821594), Z_T1_R3 = c(0.963349308, 0.968589683), Z_T2_R1 = c(3.765036263, 0.477443352), Z_T2_R2 = c(1.901023385, 0.832736132), Z_T2_R3 = c(1.407713024, 0.911920317), Z_T3_R1 = c(0.988333629, 1.095130142), Z_T3_R2 = c(0.618606729, 0.497458337), Z_T3_R3 = c(0.429823986, 0.471389536)), .Names = c("Gene", "X_T0_R1", "X_T0_R2", "X_T0_R3", "X_T1_R1", "X_T1_R2", "X_T1_R3", "X_T2_R1", "X_T2_R2", "X_T2_R3", "X_T3_R1", "X_T3_R2", "X_T3_R3", "Y_T0_R1", "Y_T0_R2", "Y_T0_R3", "Y_T1_R1", "Y_T1_R2", "Y_T1_R3", "Y_T2_R1", "Y_T2_R2", "Y_T2_R3", "Y_T3_R1", "Y_T3_R2", "Y_T3_R3", "Z_T0_R1", "Z_T0_R2", "Z_T0_R3", "Z_T1_R1", "Z_T1_R2", "Z_T1_R3", "Z_T2_R1", "Z_T2_R2", "Z_T2_R3", "Z_T3_R1", "Z_T3_R2", "Z_T3_R3"), class = "data.frame", row.names = c(NA, -2L))

I want to average reach 3 replicates (R1,2,3) for each time point (T0,1,3,5) and make a new matrix and then create a heat map with dendrogram.

How can I average each 3 replicates of each genotype at particular time point and make the new matrix? is this possible with tydr? 
since no one has replied, following is the answer gene vs time heatmap. Data frame (df) is constructed from OP data and replicates are average (mean).


    library(tidyr)
    library(dplyr)
    library(ggplot2)
    
    df2=gather(df,k,expression,-Gene) %>%
        separate(k,c("sample","time","replicate"))%>%
        group_by(Gene,sample,time) %>%
        summarise(mean=mean(expression))
    
    ggplot(data=df2,aes(time, Gene, fill=mean)) +
        geom_tile()+
        scale_fill_gradient(low = "green", high = "red")

<a href="https://ibb.co/gCo4NJ"><img src="https://preview.ibb.co/feCW2J/Rplot01.png" alt="Rplot01" border="0"></a>